In fact, all buildings move. This truth, which physics must tell us because human perception cannot, renders clear two humbling points: much of the world is not as solid as we think, and humans are awfully poor receptors. The Pentagon moves. Madison Square Garden moves. Even the Pyramids move. Perhaps only on a miniscule scale and during the most severe windstorms, but every material and structural system must deform under its load. Nothing, according to physics, can be infinitely rigid.
SOM in the Press
How Much Do Skyscrapers Actually Move?