Harold Camping, a Christian radio broadcaster who heads the Family Radio Worldwide ministry, predicts that the Rapture (when Jesus Christ will return to earth and take true believers to heaven) will take place May 21, 2011. Furthermore, the end of the world will take place Oct. 21 when all non-believers will die, he says. His predictions have garnered worldwide attention with billboards and broadcasts being used to publicize the idea. Camping’s prediction follows a long tradition of so-called “doomsday” theories. Take a look at just a few more here.