the future, wouldn't that be nice

"Globus Cassus is a utopian project for the transformation of Planet Earth into a much bigger, hollow, artificial world with an ecosphere on its inner surface. Sunlight would enter through two large windows, and gravity would be provided by centrifugal force. Humans would live on two vast regions that face each other and that are connected through the empty center.

Globus Cassus was proposed by architect and artist Christian Waldvogel and presented at the Venice Architecture Biennale in 2004."

{ more info on Wikipedia, Damn Interesting and Globus-cassus.org ...}