Modern Olympic history is full of heart-thumping victories and painful defeats. But a look back at the 28 Summer Games that have taken place since 1896 also offer a snapshot of geopolitics, a shift in women’s rights and the state of global affairs.

From Athens to Rio, in the last 125 years, the Games have crossed five continents, added and removed events, withstood boycotts and were only canceled three times due to two World Wars. Below is a timeline of notable moments in Summer Olympic Games history.

After a 1,500-year hiatus, the Games return to Athens, the ancient birthplace of the Olympic Games, where 14 nations are represented by all-male athletes. The highlight of the first modern Olympics is the marathon, won by Greece's Spyridon Louis. With 43 events, including track and field, gymnastics, swimming, cycling, weightlifting, wrestling, tennis, fencing and more, the track and field events take place in a renovated Panathenaic Stadium, which dates back to 330 B.C. American James Connolly takes home the first gold medal of the competition, winning the triple jump. Connolly goes on to win silver in the high jump and bronze in the long jump.

Held as part of the Paris World’s Fair, the 1900 Games span five months, with 20 events and 24 countries represented. Because events are so spread out, many athletes and officials don't even realize they are competing in the Olympics. But the 1900 Games introduce several new sports, including rugby, golf, cricket and croquet (the only year croquet is played), as well as equestrian events, archery and soccer. Swimming races take place in the Seine River and five sports—tennis, polo, soccer, rowing and tug of war—include athletes from differing nations playing on the same teams. It’s also the first time women participate, with 22 competing (along with 975 men). American Alvin Kraenzlein shines during the Paris Games when he takes gold in four track and field events.

Also tied to the World’s Fair, the 1904 Games are held in St. Louis over several months, with just 12 countries represented and U.S. athletes accounting for almost 85 percent of participants. Of the approximately 100 sports offered, women are only allowed to compete in archery and it’s the first time freestyle wrestling, the decathlon, boxing and dumbbells are added. American gymnast George Eyser, who competes using a wooden leg, makes headlines for snagging six medals, three of them gold. The 1904 marathon is among the Games’ most infamous. Runners slog through 90-degree heat on a busy, dusty road. By the end, more than half of the runners withdraw from exhaustion. The eventual winner, Thomas Hicks, is fed egg whites, strychnine and brandy and is carried across the finish line.

Relocated to London with little notice after Rome is forced to cancel, following the eruption of Mount Vesuvius, the 1908 Olympics marks the longest Games in history. Twenty-two nations compete in events over a six-month period. For the first time, swimming and diving competitions are held in a pool. The Games also see the introduction of field hockey, indoor tennis, and motorboating.

Although the Games are well-organized and feature a new emphasis on officiating, they are not without controversy. Several Irish athletes boycott the Games rather than participate as British crown subjects. Ralph Rose, an American shot-putter, refuses to dip the U.S. flag in salute of the king. And Finnish athletes protest Russian rule in their country. In the grueling marathon event, Italian runner Dorando Pietri collapses near the finish line but wins the hearts of spectators.

The first Asian country to participate, Japan joins the 1912 Olympic Games in Stockholm, Sweden, which includes athletes from 28 nations representing all five continents and features the debut of women's swimming and diving and the modern pentathlon. Finnish long-distance star Hannes Kolehmainen, one of the "Flying Finns," wins three golds in the 5,000-, 10,000- and 12,000-meter runs. And American Jim Thorpe, a future pro football and baseball star, becomes a household name after winning gold in the pentathlon and decathlon and taking fourth in the high jump and seventh in the long jump. But controversy surrounds Thorpe: He’s disqualified for playing for a resort baseball team a few years before the Games, a violation of IOC rules (the medals were restored in 1982, nearly three decades after his death). The 1912 Games are noted as the first time electronic timing is used, a public address system, the only time boxing doesn't take place (Swedish law banned it) and the first time an athlete dies during the Games (Francisco Lazzaro, of Portugal, during the marathon).

With World War I raging, the 1916 Olympics, slated to take place in Berlin, are canceled.

Following the devastation from World War I, Antwerp, Belgium is awarded the Games, and Germany, Austria, Hungary, Bulgaria and Turkey are not invited. The newly-formed Soviet Union does not attend. With some 2,600 athletes (about 60 of whom are women) from 29 countries competing in 156 events, the five-ring Olympic flag debuts during the Opening Ceremony. American Ethelda Bleibtrey wins all three women's swimming events, Italian Nedo Nadi takes gold in five of six fencing competitions and Swede Oscar Swahn snags silver in the team double-shot running deer event at age 72, making him the oldest medalist in Olympic history.

During the Paris Games, some 3,000 athletes (135 women) from 44 nations participate in 126 events with 1,000-plus reporters on site. Olympic firsts include the first standard 50-meter pool with marked lanes, the first formal closing ceremony and the first time athletes are housed in an Olympic village. It also marks the last time tennis is played for 64 years. American swimmer and future "Tarzan" actor Johnny Weissmuller takes three gold medals and a bronze in water polo, "Flying Finn" Paavo Nurmi wins five golds in track and field and British runner Eric Liddell, later immortalized in the Academy Award-winning film "Chariots of Fire," wins gold in the 400-meter dash and bronze in the 200, while his teammate, Harold Abrahams, also a focus of the movie, wins the 100-meter dash.

The 1928 Amsterdam Olympics feature 2,883 athletes from 46 nations (Panama, Malta and Rhodesia join) competing in 109 events. It's the first time the Olympic Flame is lit in a cauldron and the start of the tradition of Greece leading the Parade of Nations during the Opening Ceremony, with the host team closing the procession. Germany returns to the Games for the first time in 16 years and it’s the first time women's track and field and women's gymnastics are added. Henry Pearce, an Australian rower, earns gold despite stopping part-way through his quarter-final race to let a duck family pass by. Weissmuller returns with two gold medals and Japan's Mikio Oda becomes the first Asian gold medalist when he wins the triple jump.

In the midst of the Great Depression, the 1932 Los Angeles Games includes teams from 37 nations with just 1,334 athletes taking part in 117 events. Despite the timing, 100,000 spectators attend the Opening Ceremony at the Coliseum stadium, the size and quality of which would become the new standard in Olympic Games. The 1932 Games also begin the traditions of a shortened 16-day schedule (previous Games lasted a minimum of 79 days; they have lasted 15 to 18 days since) and the recognition of medal winners on a podium. The 1932 Games do not feature soccer but do include the first race-walk competition. Among only 126 women participating in a maximum of three events each, American Babe Didrikson wins two golds and a silver in track and field and Helene Madison wins three swimming gold medals.

With the Nazi Party in power since 1933, controversy swirls around the 1936 summer Games held in Berlin, with Adolf Hiltler providing the official opening. Although several countries, including the United States, threaten to boycott the Games, none officially do so, although many Jewish athletes choose to boycott as individuals. During the Games, anti-Jewish signs are temporarily removed as the Nazi regime wages a propaganda campaign to show a falsely tolerant Germany.

Nearly 4,000 athletes from 49 nations compete in 129 events, with basketball, field handball and canoeing making debuts. The first Olympic torch relay takes place, with a lit torch carried from Olympia, Greece to Berlin. It’s also the first time the Games are broadcast on television. Despite the racist Nazi agenda, Black American athlete Jesse Owens is the standout of the Games as he picks up four gold medals in track and field. American Marjorie Gestring becomes the youngest female to win gold at age 13 in the springboard diving competition.

Set to take place in Tokyo, a first for a non-Western country, Japan's award to host the Games is forfeited with its invasion of China and the Sino-Japanese War. Helsinki, Finland is ready to step in, but with Germany's 1939 invasion of Poland and the onset of World War II, the 1940 Olympic Games are canceled.

Awarded to London, the 1944 Games are also canceled due to World War II.

The Olympics return after a 12-year hiatus, with London hosting teams from 59 countries. Most events are held at a converted Wembley Stadium, as the city, still in post-war recovery, has little time or funding to construct new facilities. Japan and Germany are not invited because of their roles in the war, and the Soviet Union chooses not to attend. But several nations, including Puerto Rico, Syria, Burma and Lebanon, make their Olympic debuts.

The 1948 Games mark the first time starting blocks are used in sprint competitions and see the first covered pool. It’s also the first time the Games are televised in homes, though it was rare for Brits to own TVs at the time. American Bob Mathias wins in the decathlon at the age of 17, making him the youngest winner of a men's event (a record that endures today). Dutch runner Fanny Blankers-Koen becomes the first woman to win four gold medals in a single Olympics.

Israel makes its Olympic debut at the Helsinki Games, as does the Soviet Union as a communist nation. The United States edges out the USSR 76-71 in the medal count during the first Games of the Cold War era, and the Soviet gymnastics team begins its four-decade medal streak. A record 5,000 athletes representing 69 nations attend, and women are allowed to compete with men in mixed equestrian events. The standout of the Games is Emil Zátopek, a Czech runner who wins three golds—in the 5,000-meter, 10,000-meter and the marathon, a race he ran for the first time ever.

Held in Oceania for the first time, the Melbourne Olympics take place later in the year to coincide with summer in Australia. It’s also the first time the Games are boycotted: the Netherlands, Spain and Switzerland refuse to attend in protest of the Soviet invasion of Hungary (Hungary does attend the Games). China also boycotts because Taiwan is participating as its own nation. Equestrian competitions are held in Stockholm in June because of Australia’s strict quarantine restrictions for animals, the only time events have been held in different cities and at different times. East and West Germany compete under one flag, and, for the first time, athletes from different teams enter the Closing Ceremony mingled together, rather than alphabetically, as a symbol of unity.

The American men's basketball team dominates the competition, and the so-called "Blood in the Water" water polo match between the USSR and Hungary leads to a near riot. Hungary goes on to win the gold in the event.

Held on the banks of the Tiber, Rome hosts its first modern Olympic Games with events taking place in historical locations, including the Caracalla Baths and Basilica of Maxentius. Televised in Europe, the United States, Canada and Japan, the first Olympic Anthem debuts and approximately 5,300 athletes (611 women) compete for 83 countries. Ethiopia's Abebe Bikilaran becomes the first Black African gold medal winner when he wins the marathon—running it barefoot. American runner Wilma Rudolph scores three gold medals. And Cassius Clay shoots to pre-“The Greatest” fame, taking first in the light-heavyweight boxing category.

With Emperor Hirohito providing the official opening, Tokyo's hosting of the Games signals the first time the event is held in Asia. Awarded the canceled 1940 Games, Japan's 1964 Olympics are the first to broadcast around the globe and feature the debuts of men's judo and volleyball for both men and women, as well as the use of the hand-held stopwatch and a fiberglass pole vaulting pole. Hiroshima native Yoshinori Sakai, born on Aug. 6, 1945, the day the atomic bomb was dropped, lights the Olympic cauldron. Also making headlines: Native American Billy Mills comes from behind to win the 10,000-meter run, Ethiopian Abebe Bikila wins a second gold in the marathon, the first athlete to win the race twice, and the Japanese top the Soviets in women's volleyball.

The 1968 Olympics mark the first time the Games are held in Latin America. The Mexico City Olympics are also the first to see a woman light the cauldron (Enriqueta Basilio, a Mexican hurdler). With more than 5,500 athletes from 112 teams competing, the Games require gender testing and doping tests of winners for the first time. It’s also the first time electronic scores become standard. Czech gymnast Vera Caslavska wins four golds and two silvers. American Bob Beamon sets a long-jump Olympic record that has yet to be topped. And George Foreman earns the super heavyweight gold boxing medal for Team USA.

The high altitude of Mexico City, at almost 7,400 feet, is controversial (sprinters smash world records while long-distance times are significantly slower). But perhaps the most iconic image from the 1968 Games is the protest made by Black Americans Tommie Smith and John Carlos, the gold and bronze medal winners in the 200 meters. At the podium, Smith and Carlos raise black-gloved fists with their heads hung down during the playing of the "Star-Spangled Banner." They are suspended and ordered to leave the Games.

The Munich Olympics are the largest yet, with 7,000 athletes from 121 nations competing in a record 195 events. American swimmer Mark Spitz shines with seven gold medals and seven world records. New sports include kayaking, slalom canoeing and men's indoor handball. Archery makes its first appearance in 52 years and Soviet gymnast Olga Korbut steals the hearts of fans. But that is all overshadowed by a September 5 terrorist attack that saw eight Palestinian members of the group Black September storm the Olympic Village, killing two members of the Israeli team and taking nine others hostage. The massacre ends with all nine Israeli hostages, five terrorists and one policeman dead. Officials suspend the Games for 34 hours before continuing.

Hosted for the first time in Canada, the Montreal Olympics add women's basketball, handball and rowing to the competitions. The most notable performances come from 14-year-old Romanian gymnast Nadia Comaneci who scores the first perfect 10 in Olympic history—then proceeds to earn six more, plus three gold medals. Bruce Jenner (now Caitlyn Jenner) shatters the decathlon record, winning gold. Edwin Moses wins the 400 hurdles and Sugar Ray Leonard, Leon Spinks and Michael Spinks reign in the boxing arena. But also making headlines is a boycott by more than 20 mostly African nations. Led by Tanzania, the protest is against the IOC for allowing New Zealand to compete, despite the fact that its rugby team, the famed All Blacks, had toured apartheid South Africa, which was under a global athletics embargo. The ban leads to $1 million in Canadian dollar refunds and keeps top track and field teams from participating.

Nearly 70 countries boycott the 1980 Olympics, held in Moscow, in a protest led by the United States and President Jimmy Carter against the 1979 Soviet invasion of Afghanistan. While some athletes from boycotting countries still participate under the Olympic flag, Carter states that any American athletes traveling to the Games would forfeit their passports. The boycott leads to the fewest number of participating countries since 1956, with 80 nations attending.

In retaliation for the U.S.-led boycott of the 1980 Moscow Games, a Soviet-led boycott of the Los Angeles Olympics keeps 14 Eastern Bloc nations from participating. But the boycott has little effect on the success of the Olympics, which net a $223 million profit and attract a record-setting 140 nations. U.S. President Ronald Reagan gives the official opening of the Games and fans cheer as Americans Joan Benoit wins the first women's marathon. Carl Lewis takes home four gold medals in track and field events. And gymnast Mary Lou Retton scores a perfect 10 to clinch the women's all-around.

New sports added include the women's cycling road race, synchronized swimming, rhythmic gymnastics and the women's 3,000-meter. That last race grabs headlines when U.S. runner Mary Decker is clipped by South African runner Zola Budd, running for Great Britain. The image of Decker crying in pain and frustration is one of the most iconic in Olympic history.

A boycott by North Korea, joined by Cuba, Ethiopia and Nicaragua, for not being allowed to co-host the Games doesn't slow the Seoul Olympics, with a record 159 nations competing. Notable names from the 1988 Games include Americans Greg Louganis, who wins double gold in diving, and Matt Biondi, who wins seven medals, including five golds. American sprinters Florence Griffith Joyner wins three golds, and Jackie Joyner-Kersee takes gold in the long jump and heptathlon. German swimmer Kristin Otto sets an Olympic women's record with six golds. Table tennis is added and tennis returns after being absent for 64 years. Pros are allowed to compete in tennis and Germany's Steffi Graf wins gold. But the event is not without scandal. Canadian sprinter Ben Johnson is disqualified after testing positive for steroids, a controversial boxing decision is made against a South Korean athlete and reports of poor residents being ousted from their homes to make the city look better for travelers makes headlines.

The Barcelona Games kick off with the now-iconic image of Paralympic archer Antonio Rebollo lighting the Olympic torch with his arrow during the Opening Ceremony. It serves as a spectacular start to the Games that feature a reunified Germany competing as one nation, the USSR splintered into 15 countries with the fall of the Soviet Union and the return of South Africa, following the end of apartheid. Baseball is officially made a medal-winning sport and badminton and women's judo debut. Crowds cheer Belarusian Gymnast Vitaly Scherbo, American sprinters Carl Lewis and Gail Devers, boxer Oscar de la Hoya and swimmers Janet Evans and Summer Sanders. Spain's Carlos Front, an 11-year-old coxswain, becomes the youngest to compete in the Games in 92 years. But, really, the 1992 Games were all about the "Dream Team," the U.S. men's basketball roster with superstars such as Michael Jordan, Larry Bird and Magic Johnson, who easily win gold.

For as much as there was to celebrate at the Atlanta Games—the attendance of all 197 invited nations, more than 10,300 athletes participating in 271 events, a memorable Opening Ceremony with President Bill Clinton giving the official opening and Muhammad Ali lighting the torch—the Games are marred by a terrorist attack at the Centennial Olympic Park. A pipe bomb in a backpack explodes, leaving two dead and 110 injured. Security guard Richard Jewell is first thought a hero, then considered a prime suspect and is eventually cleared. The actual bomber, Eric Rudolph, isn't captured until 2003. Sports added to the Games in 1996 include beach volleyball, women's soccer, mountain biking, lightweight rowing and softball. Pros are allowed to compete in cycling and soccer. The U.S. women are a dominating force, taking gold in basketball, soccer, softball and gymnastics. And in swimming, Amy Van Dyken wins four golds, a first for an American woman.

With a return to Australia, 10,600-plus athletes from 199 teams compete in the 2000 Games. North and South Korea march under one flag and it’s the first time EPO detection and blood tests are used. American track star Marion Jones wins five medals in 2000, but loses them in 2007 after admitting to using performance-enhancing drugs. Newly added sports include taekwondo and the triathlon and women compete in weightlifting and the modern pentathlon for the first time. Perhaps the breakout star of the Olympics is a teenager: At age 17, Australian swimmer Ian Thorpe breaks his own world record to win the 400-meter freestyle. He also takes gold in two relays and wins two silvers.

A return to Athens, the birthplace of the Games, features 201 teams, a record number, in an Olympics that honors both the present and past. The marathon traces the 1896 route from Marathon to the Panathenaic Stadium. New sports include women's wrestling and new teams attending include Kiribati and Timor Leste. While several athletes face doping charges, American swimmer Michael Phelps sets a single-Olympics record with eight medals, including six gold. The U.S. softball team crushes the competition, outscoring all opponents 51-1 and the Argentinian men's soccer team gives up zero goals as it cruises to victory. In an upset, the U.S. men's basketball team is defeated by Argentina (led by NBA star Manu Ginobili) and has to settle for bronze. German kayaker Birgit Fischer becomes the first Olympian to win two medals in five different Games.

The Beijing Games, a first for China, sets a new bar for the Opening Ceremony, with a reported $10 million-plus price tag, 15,000 performers and spectacular special effects. More than 130 Olympic records and 40 world records are shattered, with events held in both state-of-the-art facilities and ancient areas. With a record 204 teams competing, several nations, including Afghanistan, Mongolia, Togo and Panama win their first gold medals. BMX and the 10-kilometer swimming marathon are newly added and the biggest standouts of the Games are American swimmer Michael Phelps, who wins a whopping eight gold medals, and Jamaican sprinter Usain Bolt, who wins three golds in the 100- and 200-meters and the 4X100 relay.

Held in Great Britain for the third time, the London Games include at least one female competitor from every delegation with Saudi Arabia entering women for the first time and Team USA consisting of more women and than men. Sports added include women's boxing and tennis mixed doubles, while baseball and softball are cut from the lineup. Notable wins go to Usain Bolt, who earns three more gold medals for Jamaica, American Missy Franklin who, at 17, snags four golds and a bronze, Michael Phelps, whose four golds and two silvers make him the most decorated Olympian ever and the victorious U.S. women's gymnastics team, led by Gabby Douglas. South Africa's Oscar Pistorius makes history as the first amputee to compete in the Games—he is eliminated in the 400-meter semifinal.

The first Olympics hosted in South America get off to a rocky start in Rio de Janeiro as Brazil faces a growing number of Zika virus cases and construction delays, but they still give fans plenty to cheer about. First-time events include women's rugby and returning after long hiatus are golf (112 years) and men's rugby (92 years). Among the headlines: Ibtihaj Muhammad, a U.S. fencer, becomes the first American athlete to compete in the Games in a hijab, more than 100 Russians are banned for doping, Jamaican Usain Bolt adds three more gold medals to his collection, U.S. gymnast Simone Biles wows with four golds of her own, including individual and team all-around, plus a bronze, and swimmer Michael Phelps brings another five gold medals to Team USA, while teammate Katie Ledecky, at age 19, comes home with four golds and a silver. Venus Williams, Kerri Walsh Jennings and Alison Felix are also American standouts.

The Tokyo Games were originally scheduled to take place in July and August 2020 but were postponed due to the coronavirus pandemic. While the Olympic Games kick off on July 23, 2021, these Olympics are unlike any other. Two weeks before the Games were set to begin, a state of emergency was declared in Tokyo due to an uptick in coronavirus cases. The Olympic organizing committee decides to ban spectators from events and all athletes are tested regularly and adhere to social distancing measures. Some athletes test positive for the virus ahead of the Games, including American tennis hopeful Cori "Coco" Gauff, players on the South African soccer team and an alternate for the U.S. women's gymnastics team. Even though the Tokyo Games begin in July 2021, they are officially referred to as Tokyo 2020.

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