Throughout history, the US government has engaged in - or encountered - all manner of covert, nefarious, and sometimes just downright strange operations. From research into paranormal phenomena to secret acid tests to UFO sightings, most of these programs were classified and sealed from the public eye, often for decades.
These programs are sometimes sealed for national security reasons or to protect "sources and methods" within the intelligence community. Other times, they're sealed because the information itself could prove damaging to the government - either because they're up to something they shouldn't be, or because someone else is.
Nothing stays classified forever, though, and sooner or later, the documentation of even the creepiest and most objectionable secret projects is declassified - often with very little fanfare, since, even years later, the government doesn't want to advertise some of the dark secrets they've been privy to over the years.
Here are some of the creepiest and weirdest declassified documents that you can read right now - and the bizarre and sometimes terrifying revelations they contain.