Brigadoon
From Omnictionary
A city in Scotland, which has the miracle of disappearing for about 99 years at a time. It is theorized that, since the position of Brigadoon is known, and the position of Xanadu can be approximated, the position of El Dorado should be somewhere in Kansas. Using this logic, conquistador and alleged Decepticon Coranado sought there but found only buffalo and liars.
