After having sustained significant damage amidst an orbital bombardment by space aliens, the EOD training facility codenamed "Keystone" underwent renovations to comply with local safety codes. The compromised structural integrity of the floor was remedied by removing the floor altogether.
Keystone 2000 is an experimental successor to Keystone. It has a modified structure, new lighting, and new texturing.
Note: You will need SVN to load the map.
Update: Now with waypoints. Bridge geometry has been fixed and clipped.