More than a year after fighting broke out between colonial militia and British forces in April 1775, the Continental Congress in Philadelphia finally decided to declare the independence of the North American colonies. The main goal of the Declaration of Independence, adopted on July 4, 1776, was to present the colonists’ grievances against Great Britain, but it would be Thomas Jefferson’s introductory words (“We hold these truths to be self-evident; that all men are created equal; that they are endowed by their Creator with certain inalienable rights…”) that would echo most strongly through generations to come.

After several failed attempts at creating a government, a 1787 convention is called to draft a new legal system for the United States. This new Constitution provides for increased federal authority while still protecting the basic rights of its citizens.

In the earliest years of the new nation, many people opposed the Constitution because they thought it gave the federal government too much power over its people. As soon as the new U.S. Congress met, it began debating a number of constitutional amendments, the first 10 of which were ratified in December 1791 as the Bill of Rights. By guaranteeing certain fundamental rights—including freedom of speech and religion, the right to bear arms and the right to a fair trial—against infringement by the federal government, the Bill of Rights greatly expanded the civil liberties of Americans, with implications that are still being debated today.

By 1862, President Abraham Lincoln had become convinced that freeing the South’s slaves was critical to the Union effort to win the Civil War. Though the Emancipation Proclamation, which took effect the following year, applied only to the slaves in Confederate states, Lincoln made it clear in his historic Gettysburg Address that the Union now fought to provide a “new birth of freedom” rather than simply bring the South back into the fold. Passage of the 13th Amendment to the Constitution in 1865 abolished the institution of slavery, and granted liberty to more than 4 million black men, women and children formerly held in bondage.

“Give me your tired, your poor/Your huddled masses yearning to breathe free,” the poet Emma Lazarus imagined the Statue of Liberty saying to the world in her famous sonnet “The New Colossus.” From 1880 to 1920, more than 20 million immigrants came to the United States seeking freedom and new opportunity.

Whether they were fleeing religious persecution (Eastern European Jews), hunger and poverty (Italians), or war or revolution at home (Armenia and Mexico), the United States welcomed these new arrivals—with the notable exception of people from Asian countries, whose entrance was strictly limited by laws such as the Chinese Exclusion Act of 1882. This relatively open-door policy ended with the onset of World War I, and in the 1920s a series of new laws would be introduced to limit immigration.

Some 72 years after the national women’s rights movement launched at Seneca Falls, ratification of the 19th Amendment in 1920 finally gave women the right to vote. Despite setbacks and internal divisions in the decades after the Civil War, the suffrage movement gained momentum in the early 20th century, as protesters were arrested, imprisoned and in some cases went on hunger strikes for the cause.

After Tennessee became the last necessary state to ratify the 19th Amendment in August 1920, women across the country headed to the polls to exercise their long-awaited right to cast their ballots in the presidential election that fall.

“People of western Europe…the hour of your liberation is approaching,” General Dwight D. Eisenhower, supreme commander of the Allied Expeditionary Force, announced in a speech broadcast via radio on June 6, 1944.

By the end of that day, some 156,000 American, British and Canadians forces had landed simultaneously on five beachheads in northern France, beginning the Allied invasion of Western Europe during World War II. As Eisenhower’s speech had predicted, the triumphant landing marked the beginning of the end for Adolf Hitler’s Nazi forces, which would surrender unconditionally less than a year later.

After years of struggle and setbacks, advocates for equality celebrate the passage of sweeping legislation that prohibits racial discrimination.

In 1963, as civil rights activists protesting segregation and voting restriction across the South met with violent opposition, and hundreds of thousands of people marched on Washington to demand “Jobs and Freedom,” President John F. Kennedy introduced the first major civil rights legislation since Reconstruction.

After JFK’s assassination that November, his successor Lyndon B. Johnson took up the cause, doggedly pushing the bill through stiff Democratic opposition in Congress. On June 2, 1964, Johnson signed into law the Civil Rights Act, which ended the segregation of public and many private facilities, and outlawed discrimination based on race, color, religion, sex or national origin.

On June 26, 2015, the Supreme Court issued a landmark ruling declaring that the Constitution guarantees to same-sex couples the freedom to marry. The case that led to this milestone achievement for the gay rights movement, Obergefell v. Hodges, began when same-sex couples sued in Ohio, Michigan, Kentucky and Tennessee, declaring that their states’ bans on gay marriage were unconstitutional.

In a decision that echoed the Court’s 1967 verdict in Loving v. Virginia, which struck down state laws banning interracial marriage, Justice Anthony Kennedy declared that the freedom to marry was one of the most fundamental liberties guaranteed to individuals under the 14th Amendment, and should apply to same-sex couples just as it does to heterosexual couples. “They ask for equal dignity in the eyes of the law,” Kennedy wrote. “The Constitution grants them that right.”