As Vizzini infamously reminds Westley in The Princess Bride, "Never get involved in a land war in Asia." It's one of the classic blunders, yet it's a mistake many conquerors have made. You could say those plans backfired massively, but Napoleon, Big H, and others are far from the only world leaders to have made huge mistakes. In this gallery we've collected some of the worst plans from history, and how they backfired. 

One of those plans came courtesy of the British Empire when they wanted to cut down on the poisonous snake population in India during the early 1900s. Also called the cobra effect, England offered a bounty for every cobra caught and killed. In response, people bred and killed massive numbers of cobras, ultimately increasing the cobra population. 

Read about that plan and others from history that didn't go well.