<"You probably know all about that..."

I did not. I just am extremely interested in human evolution, history, and civilization, and my research into Denisovans eventually has intersected with the several rabbit holes you mention above. The involvement of Ales Hrdlicka of the Smithsonian Institute in the disappearance of numerous skeletons found in mounds in the USA is pretty blatant. More than 1000 reports of skeletons over 7' tall were published in the 19th Century, and Hrdlicka was funded and positioned to be the guy to contact for such reports. Skeptics about the concealment of such artifacts can find other examples much more recent, such as the US Parks Dept. burning artifacts and remains in the 1970s.

History is full of holes, and it turns out they're all rabbit holes.