This is amazing, especially for what they had in 1930!

Also, it sort of reminds me of those Foucault pendulums, where the pendulum moves so slowly that you can't notice it, but after a few hours, it moves quite a bit. It's sort of like that, you don't even know the building's moving, but a month later, it's been fully turned!

edit: why was I downvoted? :(