Galileo is in my view one of the coolest people in history. I also particularly like the final resting place of his body, in Santa Croce in Florence, Italy, where he is honored alongside the likes of Rossini, Fermi, and Michelangelo (another favorite).
While famous for his (purported) “Eppur Si Muove” regarding planetary motion, Galileo did a lot of earthly physics as well. In describing falling objects he noted that without air resistance a hammer and a feather would fall at the same rate.
Evidently this video has been around since, well, 1971, but I had never seen it before. Apollo 15 Commander David Scott drops a hammer and feather and observes that they land at the same moment.
Now if someone would just try this with a hammer and sickle...