Lunar Surrogate

Starting in 1963, the American Astrogeology Research Program played an important role in training astronauts destined to explore the lunar surface and in supporting the testing of equipment for both manned and unmanned missions.

A few years before the first landing on the moon, scientists recontoured a volcanic field just outside of Flagstaff, Arizona, with artificial impact craters resembling those found on Mare Tranquillitatis, the proposed first manned American landing site. With high explosives, they terraformed a lunar surrogate right here on the surface of the earth.

(via Dark Roasted Blend)