what is the piltdown man hoax? and what happened?

Answer 1

Jaw of an orang utan, attached to the skull of an otherwise modern human.

http://en.wikipedia.org/wiki/Piltdown_Man

Hope this helps!

Answer 2

As I understand it the skull was chemical treated and ruffed up to look older than it really is. Planted beside a bush and found by the Dr. who planted it with an aid or another Dr. witnessing that.
Now that DNA testing is done it shows to be a hoax. by mixing species