This is my favorite building in Boston. I always called it the "Escher" building after his artwork because of all of its bizarre staircases that twist and turn and often appear to be upside down. Created by Paul Rudolph in the 60s or 70s, this building is massive and has a huge courtyard in size and has a huge courtyard in back. Sadly it is greatly ignored. Many people find the building very ugly, but it has so many nooks and crannies, it is just a fascinating place to explore, and when you do...you will probably be all alone, too.