This amazing blend of art and science is called a “Foucault Pendulum”. There are a lot of big words and equations that are used to describe how and why it all works, but I’ll spare you all that (mainly because I don’t understand it) and here’s the short and easy version: The giant pendulum swings from the ceiling while the ornate floor, with upright rubber mallets moves along with the Earth’s rotation underneath it. As the Earth rotates, the pendulum strikes the standing mallets at certain intervals throughout the day and they in turn strike a xylophone like key and a musical tone is heard every time one falls. On paper, it sounds boring as heck, but in person, it was great fun to watch.