Built by an army of more than 21,000 workers, the 60-story-tall Hoover Dam was the world’s largest concrete structure and highest dam at the time it was dedicated in 1935. The project, which required the Colorado River’s diversion through four excavated tunnels, finished two years ahead of schedule.

The arch-gravity dam on the Arizona-Nevada border controls the flow of the Colorado River, stores enough water to irrigate 2 million acres and powers more than 1 million homes with hydroelectricity. The Hoover Dam propelled the development of cities such as Las Vegas and Phoenix and created Lake Mead, the largest reservoir in the United States in terms of water capacity.

One of the major construction projects the PWA helped finance was the New York City’s Triborough Bridge (now the Robert F. Kennedy Bridge), which connected Manhattan, Queens and the Bronx.

The powerful New York City official Robert Moses led construction of the bridge, which opened in 1936. At the dedication ceremony, FDR placed the bridge within the larger context of New Deal projects, saying, “People require and people are demanding up-to-date government in place of antiquated government, just as they are requiring and demanding Triborough Bridges in the place of ancient ferries.”

In the late 1930s, the city of San Antonio secured funding from the WPA to improve infrastructure along the San Antonio River. The city used this money to build bridges and pathways that made the area more walkable and allowed businesses to move into the area. Today, the River Walk is a major commercial and tourist hub for the city.

The WPA funded the construction or improvement of roughly 800 airports, and one of the biggest ones the WPA helped build was LaGuardia Airport in Queens, New York. When it opened in 1939, it was known as New York Municipal Airport. Later, the city changed the named to honor Fiorello La Guardia, who was New York City’s mayor when the airport opened.

In addition to buildings and roads, the WPA also funded works of art, including a mural that artist James Brooks painted inside the Marine Air Terminal.

In 1933, New Deal legislation created a public corporation to improve the Tennessee Valley. One of the biggest projects that this corporation, the Tennessee Valley Authority, took on was the Chickamauga Dam, located on the Tennessee River outside of Chattanooga.

Before the dam’s completion in 1940, the surrounding region frequently suffered from expensive flood damage and mosquito-borne illnesses like malaria and yellow fever. By controlling the river’s water levels, the dam has prevented billions of dollars in flood damage. It also helped reduce mosquito populations in order to fight the diseases they spread.

Yet another New York City project that the PWA helped fund was the Lincoln Tunnel. The tunnel’s center tube opened for traffic in 1937, allowing drivers to travel between New York and New Jersey under the Hudson River. Later, workers added two other tubes: the north tube in 1945, and the south tube in 1957.

Using WPA funding, New Orleans improved its City park in the 1930s by building sidewalks, bridges and an art museum. This construction likely provided work to tens of thousands of people during the Great Depression, and also benefited residents by providing them with an improved public space.

The San Francisco-Oakland Bay Bridge was a project of the Reconstruction Finance Corporation, an agency that started under Hoover but became part of FDR’s New Deal efforts to improve the country’s infrastructure. Construction began in 1933 and the bridge opened in 1936. With its eight-mile span, the Bay Bridge was at that time the longest bridge in the world.

The New Deal was also responsible for the first freeway. Both the PWA and the WPA helped fund the construction of Arroyo Seco Parkway—now known as the Pasadena Freeway or 110—which connected Los Angeles to Pasadena. The freeway opened to traffic between 1938 and 1940, and reduced travel between L.A. and Pasadena from 27 to 12 minutes.