At 3:17 p.m. ET on July 20, 1969, the Apollo 11 lander touched down on the lunar surface. For millennia, scientists, astronomers, religious thinkers, and philosophers have tossed out theories about the moon—some based more on science than others. But finally, humanity had landed on its surface.
Here are some theories we once believed about the moon, some of which the Apollo program helped disprove.