The stone posts outside the Colosseum each have holes cut into one side. A popular story says they anchored the ropes of the velarium, the huge awning that shaded the crowd. The evidence points somewhere else.

These stone posts outside the Colosseum each have holes cut into one side. Some say they once held down the biggest shade in the ancient world. It was called the velarium: a giant awning that kept the crowd out of the scorching sun, and, some say, the rain. Look up at the top rim: two hundred and forty sockets. Each held a wooden mast, standing on a stone bracket and passing up through the rim. The problem? A stadium more than six hundred feet long, and nowhere to put a single pole in the middle. The leading reconstruction: ropes ran from every mast to a rope ring hanging over the arena, pulled tight like the spokes of a bicycle wheel. Strips of cloth slid out along those ropes like curtains, shading the seats and leaving the middle open to the sky. But all that rope and cloth pulls the masts inward. The brackets held them upright, but nobody's sure they could take that strain alone. Guides will tell you these posts helped. Except the posts barely go into the ground, far too shallow for that pull. They most likely held crowd barriers. So how the masts took the strain is still argued. But that spoked ring is how many modern stadium roofs work. Rome got there two thousand years early, and all it left are holes in the stone, and these posts nobody can agree on. Subscribe for a fact every day.