Century 21: Space Needle Designs (1962)
In a way, Seattle has a permanent piece of the paleo-future.
The always amazing blog BibliOdyssey has a great post titled Century 21 Exposition. It features proposed designs for the Space Needle and the fairgrounds for the 1962 Seattle World's Fair (also known as the Century 21 Exposition).
For an amusing film following teenagers through the expo be sure to check out Century 21 Calling.