Area 51, the secretive U.S. government test site, is shrouded in mystery, and here are some Area 51 facts that separate fact from fiction. We've debunked some conspiracies and put some actual, research-based facts in their place. Of course, there is no proof of "extraterrestrial" activity present on Area 51, though many remain convinced that there's something fishy going on there. However, thanks to some declassified documents, we have learned that Area 51 is mainly used in the development and testing of spy planes. The government doesn't want you to know these Area 51 facts. When you're done checking them out, make sure to SHARE them with your friends!

Editor's Note: This piece was first published on Dec. 31, 2015. It has been updated throughout.