One of the neat things I encountered as moderator on my college's message board was a link to a site which delved into the realm of aviation archeology.
In 1967, a rare A-12 aircraft--the CIA's version of the SR-71 that was a bit shorter, faster and produced two years earlier than that aircraft--crashed on its way back to Groom Lake (Area 51). The crash site was isolated, and so much secrecy surrounded the event that the site remained untouched for decades until someone did two years' worth of detective work and uncovered the crash site. When a plane travels at well over Mach 3, you'll find that that pinpointing an exact crash site based on rough time/distance/heading leaves you with an incredible margin of error. An aircraft like that could travel through an entire state in just a few minutes.
His narrative is incredible, and what's neat is that he doesn't tell you exactly where the aircraft crashed. I'm thinking that I need to take a trip out to see if I can do some archeology work for myself.