Home to 39 profoundly damaged chimpanzees rescued from captivity across Africa and further afield, Ol Pejeta's Chimp Sanctuary encompasses two large enclosures cut in two by the Ewaso Ngiro River. There's an elevated observation post and keepers are usually on hand to explain a little about each chimp's backstory; note the tiny replica cage in which one of the chimps was chained for years on end prior to being brought to the sanctuary.
There is an information centre and you can adopt a chimp (US$100 to US$250) if you would like to help the sanctuary.