At a Chimpanzee Rescue Center in Cameroon, a chimp named Dorothy died of heart failure. What happened next was amazing: Her fellow chimps hugged each other in solidarity and solemnly watched as their friend was laid to rest.

THE SURGEON WHO OPERATED ON HIMSELF:

In 1961, Leonid Rogozov, 27, was the only surgeon in the Soviet Antarctic Expedition. During the expedition, he felt severe pain in the stomach and had a high fever. Rogozov examined himself and discovered that his appendix was inflamed and could burst at any time. With a local anesthesia, he operated himself to remove the appendix. An engineer and a meteorologist assisted surgery.