Did you know Europeans used to think California was an island?

The Island of California refers to a long-held European misconception, dating from the 16th century, that California was not part of mainland North America but rather a large island separated from the continent by a strait now known instead as the Gulf of California.

One of the most famous cartographic errors in history, it was propagated on many maps during the 17th and 18th centuries, despite contradictory evidence from various explorers. The legend was initially infused with the idea that California was a terrestrial paradise, like the Garden of Eden or Atlantis.

http://en.wikipedia.org/wiki/Island_of_California