The Hoover Dam was built to control the powerful Colorado River, which for many years flooded farms and cities.

“‘Ladies and gentlemen, here is where man conquered the mighty river placing a concrete yoke about its neck to harness its tremendous power and water resources,’” a 1955 educational video explained.

In 1922 the Colorado River Compact divvied up the water to the upper and lower basin states. This allowed for cities like Las Vegas and San Diego to mushroom rapidly, and for farmers to grow acre upon acre of alfalfa and other crops.

About 20 years later, Arizona and Mexico signed on to receive their shares.

via US, Mexico To Sign Landmark Colorado River Agreement | Fronteras Desk.