Alone on an island for 18 years.
Island of the Blue Dolphins is a work of historical fiction based on the life of an American Indian woman who spent 18 years in isolation on San Nicolas Island, one of eight Channel Islands off the coast of Southern California.
In the book she's named Karana. Her birth name is lost to history, but she's often referred to as the Lone Woman of San Nicolas Island or as Juana María, the name under which she was baptized before burial at Mission Santa Barbara.
Today, San Nicolas Island is owned by the US Navy. Although it is closed to public visitation, you can experience similar island environments, plants, animals, and history by visiting Channel Islands National Park, which protects five of the eight remarkable Channel Islands.