Solar furnace

In the late 1950s, the U.S. government built a "solar furnace" with this 60-foot-high heliostat for military and civilian purposes. By reflecting and concentrating light, it was initially designed to simulate the thermal effects of a nuclear weapon. Then in the 1970s, it was moved to the White Sands Missile Base in New Mexico to evaluate solar energy as a "viable natural resource," according to a 1975 report (PDF).