Lake Mead plummets to unfathomable low, exposing original 1971 water intake valve.
The Colorado River irrigates farms, powers electric grids and provides drinking water for 40 million people.
As its supply dwindles, a crisis looms.
California's two largest reservoirs are already at 'critically low levels' and the dry season is just starting.
Why the Great American Lawn is terrible for the West's water crisis.
Experts say the term 'drought' may be insufficient to capture what is happening in the West. »