Keiko

Keiko the killer whale was captured off Iceland in 1979, placed in an aquarium, and eventually sold to a Mexico City amusement park. While in Mexico City he was featured in Free Willy, the hit 1993 film about a boy who frees a captive whale. Keiko became a cause celebre after news reports revealed that he (ironically) was still a captive and in poor health. The Free Willy-Keiko Foundation was formed, and in 1996 Keiko moved to a custom-built tank at the Oregon Coast Aquarium. In September of 1998 the five-ton orca was flown to a special open-water pen in Iceland, to be trained for a potential return to life in the sea. He was finally released to the wild in July 2002, but two months later he turned up in the western fjords of Norway, apparently happy to be around people again. He remained in Norway until his sudden death in December of 2003, apparently from acute pneumonia.

Extra credit: Keiko was originally named Siggi after his 1979 capture... Keiko is a Japanese name meaning "lucky one."