Area 51 The History and Mystery of America's Most Controversial Military Base

In simple terms, it is a place where the United States government conducted - and continues to conduct - tests, in a remote environment where civilians are not in jeopardy and enemies from foreign countries cannot observe or sabotage weaponry or strategy the US might use against them. Assuming that other countries were doing the same, the US also used this remote site to test equipment like the U-2 that would make it possible to spy on other countries and for other countries to do harm to the United States.