Answer:
The Hoover Dam was built between 1931 and 1936. It used to be called Boulder Dam, but it was renamed in honor of Herbert Hoover, the person who made the dam possible and later became president of the United States.
To put it simply, the importance of the Hoover Dam lies in its complexity: it is one of the most amazing engineering works of the 20th century and one of the largest dams in the world. It may seem minimal to us today, but at the time it was an extraordinary construction.
Without the Hoover Dam, the city of Las Vegas would be a desert without water or energy, as well as a large part of the states of the southwestern United States.
Thanks to the existence of this dam, the famous Lake Mead was created. An artificial lake in a desert place has a more important value than we think.