The US planned to Nuke the Moon

Remember that "One small step for man, one giant leap for mankind" business during the Apollo moon landings? Well apparently, getting to the moon wasn't always a peaceful endeavor. The United States, in an effort to intimidate the Soviet Union in the Space Race, actually had plans to launch a nuclear weapon at the moon as a show of force.

Which, of course, would have been so productive (that's sarcasm, folks). The weirdest thing of all, is that astronomy superstar Carl Sagan was involved in the whole project. The same Carl Sagan that made all those TV shows and wrote "Cosmos". The same Carl Sagan that was smarter than everyone on the planet... when it came to talking about planets. The same Sagan that became a mouthpiece for world cooperation and science:

Sagan, who later became renowned for popularizing science on television, died in 1996. The author of one of Sagan's biographies suggested that he may have committed a security breach in 1959 after revealing the classified project in an academic fellowship application. Reiffel concurred. 

Under the scenario, a missile carrying a small nuclear device was to be launched from an undisclosed location and travel 238,000 miles to the moon, where it would be detonated upon impact. The planners decided it would have to be an atom bomb because a hydrogen bomb would have been too heavy for the missile. Reiffel said the nation’s young space program probably could have carried out the mission by 1959, when the Air Force deployed inter-continental ballistic missiles. 

Of course the military decided that it was too dangerous for the people on Earth to detonate a nuke on the moon. They weren't sure what the effect of the radioactive dust and fallout would do. Thankfully, the man on the Moon never got a black eye.