Left: Aerial view of Fort Snelling Visitor Center in Minnesota, constructed underground as a "nonbuilding" so as not to intrude on the historic site. Prarie ecology was planned to be restored on the roof. A restoration of the historic cemetery was planned to replace the three contemporary buildings in the middle distance. The restored original fort, at the confluence of the Mississippi and Minnesota rivers is in the background.
Below: Exit from museum toward the fort. The city of Minneapolis is visible in the distance.
Above: Longitudinal section through site and building. The colored areas indicate the location of the central corridor to the fort, and a unique "periscope" light shaft which allows people below ground to see out into a sunken courtyard.
Below: Diagram of proposed system to use stored winter cold and summer heat in underground thermal "bubbles" to modify interior temperatures and reduce energy demand.  
Above: Model of original proposal for Fort Snelling Visitor Center, to be built into river bluff, but still below ground at site level. Not executed.