The Green Building, also known to MIT-folk as Building 54 or the EAPS Building, was designed and built by I.M. Pei between 1962-1964. It's a 21-story skyscraper, the tallest building in Cambridge, although only 18 stories contain rooms. The bottom two stories consist of a giant square arch beneath the building, and the eastern and western sides are cement with no windows.

According to MIT legend, the Green Building was originally designed at ninety degrees to its current facing. The concrete sides would face towards the river and northern Cambridge, while the windows to the east and west would have equally good views of the Boston suburbs. The design was put through the appropriate wind tunnel tests and approved. Right before the paperwork was put through, however, a nameless administrator realized that if the building was turned sideways, an entire set of windows would have a river view, and correspondingly higher property value. So the papers were rotated, stamped, approved, and the building was built.

Unfortunately, the nameless administrator had also never heard of Bernoulli. Once built, the wind off of the river created a pressure differential extreme enough that there were several hundred pounds of force preventing the ground-floor doors from opening. To fix the problem, MIT hired artist Alexander Calder to create an aerodynamic statue and divert the wind. The result? The Big Sail, better known as the Great Sail, one of the few good pieces of art at MIT.

The Green Building is also the target of its own assortment of hacks, and the original site of Greenspeak.