The Hoover Dam

Fast backward to 1910. Gambling was illegal in Nevada, even flipping a coin to decide the price of a drink was forbidden. The town of Las Vegas had a booming economy as the railroad hub connecting Utah mines to California through Nevada.

Fast forward to 1931. Alcohol is prohibited in the US, the Great Depression tore apart the world in 1928 and earlier railroad bankrupcy left Vegas in a very challenging position financially. Up and down, like a roller coaster. The construction of a huge dam on the Colorado River boosted Vegas' population from 5,000 to 25,000. Gambling become legal and Maffia mobs and local business owners started to develop casinos and theaters for the contruction workers.

The Hoover Dam (then clalled Boulder Dam) provided the initial demand and later on cheap electricity to create Las Vegas as we know now. An engineering marvel, the largest of the world at the time of completiton.