MODERN MARVELS: Hoover Dam

The Hoover Dam is a concrete gravity-arch dam in the Black Canyon of the Colorado River, on the border between Arizona and Nevada.

The dam, located 30 miles from Las Vegas, is named after Herbert Hoover, who played an instrumental role in its construction, first as Secretary of Commerce and then later as President of the United States.

Before the construction of the dam, the Colorado River Basin periodically overflowed its banks when snow from the Rocky Mountains melted and drained into the river. These floods endangered downstream farming communities.

The decision was taken to dam the river to protect the communities but also to capture the water for uses in the surrounding states. The task was monumental: build the world's largest dam in the middle of the desert, and tame the river that carved the Grand Canyon - all in seven years!

Construction began in 1931 and was completed in 1936, over two years ahead of schedule. Lake Mead is the reservoir created behind the dam, named after Elwood Mead who oversaw the construction of the dam.

When the Hoover Dam was completed in 1935, it was the largest dam in the world. The Hoover Dam was designated a National Historic Landmark in 1985. We'll reveal how this engineering wonder of the world was conceived and built.