One of the greatest American conspiracy theories suggests that Neil Armstrong's famous line "One small step for man, one giant leap for mankind" was, in fact, made from the comfort of a film studio.

The conspiracy centers around the July 20, 1969, moon landing—the landing of the first men on the moon at the height of the space race.  To this day, many believe that the footage transmitted from that first landing was a forgery, nothing more than a Hollywood production made for prestige and propaganda purposes.  And at that, the attempt was flawed in many ways, which allegedly reveals its forged nature.  Yet as exciting as the idea of the United States pulling off the greatest publicity coup in the modern era may be, the theory is wrong—America really did land men on the moon.

The footage itself serves as evidence of the landing, in part because all of the points raised about its authenticity have been proven wrong by logical explanations.  One famous argument for the video being a forgery points to the absence of stars from the recordings as a clear sign.  But the simple explanation behind this point lies with the difficulty of capturing the up-close and very bright astronauts and moon surface, and the distant and dim stars, in the same film shot.  (Of course, the exposure would have been set so as to properly capture the first two!)  

Another famous accusation discusses the apparent waving of the flag that the astronauts planted on the moon, which seems suggestive of a breeze on a movie set. However, the flag was not waving in the air, as it would on Earth, but rather it rippled into that position when the astronauts only partially extended the rod and unfurled the flag, thus giving it the appearance of continuing waving.  

The glaring truth that pervades this issue as well as several other points is that if NASA really did fake the moon landing, one would have expected  them to have put in a little more time, effort and money (which they would have saved from not actually going to the moon) into correcting these seemingly amateurish mistakes. (Not to mention the fact that the Soviets would have loved to expose the moon landings as a fraud, and Russian intelligence would no doubt have investigated these mistakes thoroughly.)

Furthermore, there are the several surviving astronauts, Neil Armstrong and Buzz Aldrin included, who went to the moon (Aldrin actually punched a moon landing conspiracy theorist in the face for calling him a liar).  But for those who will not accept anything less than physical evidence, there are always the moon rocks themselves.  An examination of the moon rocks will reveal that they are devoid of the water and minerals typically found in Earth rocks, covered with small impact craters from meteoroids, and filled with isotopes created by interaction with cosmic radiation.  Either the moon rocks are genuine, or NASA and the countless, some foreign, independent institutes which have examined and displayed loaned moon rocks, are cooperating in a massive conspiracy.

While the notion that America did not land men on the moon may be an interesting theory to entertain, the simple fact is that the evidence weighs very heavily against it.