Dam

https://en.wikipedia.org/wiki/Hoover_Dam
http://zidbits.com/2013/05/how-long-will-the-hoover-dam-last/

Hoover dam-Boulder Dam
in black canyon of the colorado river
provides power for public and private utilities Nevada, Arizona, California
named after President Hoover
1931-1936 time it took to build
 In 2011, president Obama signed a bill extending supply till 2067
set aside 5% of its power for native american tribes and electric cooperative
53.5% of its total output goes to California, with 15.4% of that number going to Los Angeles alone. Arizona uses 18.9% while 23.3% is allocated to Nevada
supposed to last 10,000 years at least 
many pieces of art are around the dam
112 deaths with construction
six companies- joint construction teams (Pacific Bridge Company of Portland, Oregon; Henry J. Kaiser & W. A. Bechtel Company)


Background:
potential source of irrigation water
used dynamite to help collapse rocks around-idea was denied