The Hoover Dam - Winged Figures of the Republic.

With wings about 30 feet tall, they may be angels, or demons... or far-future humans, still benefiting from the energy output of a structure engineered for the Ages.

In an odd astrological touch, the monument is surrounded by a terrazzo floor with a celestial chart which shows the exact position of key stars on the day the Hoover Dam was dedicated by President Franklin Roosevelt. The star map would assist a future civilization of giant flying humans to pinpoint the date as September 30, 1935.