Jane Goodall hasn't exactly found the missing link, but she's come closer than just about anyone else on Earth. Her extensive research into the behavior of chimpanzees, which started in Africa in the 1960s and continues today, fundamentally altered scientific thinking about the relationship between humans and other mammals.

Goodall, who founded a research institute in her name in 1977, is an internationally recognized authority on the primate world. She's written books for adults and children, contributed to documentaries, and serves as a National Geographic explorer-in-residence, a United Nations peace messenger, and the president of Advocates for Animals. For her efforts to observe and preserve all species, Goodall has received honors and accolades from governments, nonprofits, universities, and professional organizations, including a medal from UNESCO and the French Legion of Honor in 2006.