The Biggest Mistakes That Changed History

You know when you've made a big mistake. Sure, there have been tests that you thought you aced or dates that you thought went well - but you know when you've made a really big blunder. Now, imagine that your miscalculation is so large, it changes the course of history. We're taking a look at some of the worst - and best - historical mistakes, those with effects you can still see today.

Some of these mistakes that changed history were tragic miscalculations; others were fortuitous mishaps. Read on for a list of historical events that were a mistake and their surprising consequences.