The hype over the end of the Mayan calendar on December 21, 2012 is causing people to get scared and even prepare for a possible doomsday. Only time will tell if the fears are founded, but this is only one of many doomsday predictions in history. Check out all of the times that the world was supposed to end, and didn't!
One of the earliest doomsday predictions was made by Hippolytus, a member of the Church of Rome. He calculated that the amount of time between Adam and Christ in the bible was 5,500 years, and assumed that Christ would return in the 6,000th year. This meant that the return of Christ, and therefore the apocalypse, would occur in 500 A.D. He made this prediction in 236 A.D. and was martyred soon after for his beliefs.