The crop circles first appeared in the 1970s, and people went crazy about the aliens trying to communicate with us. Even though it turned out to be a prank and the 2 guys who made it came fourth, the media kept the thing going for decades, probably because it's a great material to recycle as more and more people are trying to fool the locals with their versions of alien messages left in crops.

The Spaghetti Tree, is an April Fools prank by BBC from the mid-1950’s, that went too well. People actually thought that it was true they would be able to harvest trees for spaghetti. Science, bitch!

In 1986, Swiss anthropologist discovered the Tasaday, a tribe of indigenous men and women on the island of Mindanao. They were supposed to be cave people living away from the civilization. It later turned out that they were members of known local tribes who put on the appearance of living a Stone Age lifestyle under pressure from the Philippine government.

Clever Hans was a horse that could read and solve math equations, and answer them by tapping his hoof. It later turned out that it was his trainer who was giving the horse clues on how to tap his foot. Nice trick, but not nearly as nice as they claimed it was.

The Perpetual Motion machine that was almost accepted as legit turned out to have been additionally propelled by... and old man secretly turning it with a crank.

Shinichi Fujimura, an archaeologist from Japan gained prominence in the early 1980’s because of his findings. He even claimed that he found pieces that were 600,000 years old. His ridiculously incredible claims lead to an investigation that discovered the origin of the items found by Fujimura. He was planting them himself.

In 2002, BBC aired a report that said blonde hair would be completely gone within the next few centuries because it's a recessive trait in human beings. It turned out to be a made up assumption.

In 2000, an MIT university student, calling himself Dr. Michael Wong, claimed he had created a way to grow a kitten within a jar. The kitten, known as the Bonsai Kitten, would be in the shape of the jar. Even though this was a joke, it was taken seriously by some animal rights groups.

The biggest prank known is the World of the Worlds which refers to the 1938 radio program which made people believe that aliens invaded Earth. This is believed to have started the whole alien hype. After Orson Welles broadcast his message about the invasion, many people panicked, the prank was so elaborate and well conducted.

Dihydrogen monoxide is the chemical term for water. People who didn't pay attention in school don't seem to realize that and they keep getting fooled by the messages of dihydrogen monoxide infections. This is a great way to trick your not so bright friends into making water awareness a big thing on their Facebook status.