The footprints left by the Apollo astronauts in July 20, 1969 will remain for a long, long time because the Moon has no wind or water that can wipe the footprints out. Even the metal bar they attached the American flag to can't be removed and flown away.

The moon has no atmosphere, too. Because there's no atmosphere to trap the heat, the moon's temperatures vary dramatically, from 100 degrees Centigrade at noon to minus 173 degrees at night.

The moon consists of several craters. Craters will remain for centuries because there's no rain nor earthquake in the moon.

The footprints on the moon will be wiped out only if the meteorites or charged particles from the sun bump on the lunar surface.

Image Credit: www.flickr.com/photos/24662369@N07/4812876306 , creativecommons.org/licenses/by/2.0/deed.en