The Sunshade of the Roman Colosseum

In the height of Roman summer, 50,000 people sat for extended periods to watch games in the Colosseum, which had no stone roof. The secret? Instead of building a roof, they unfurled ship sails across the sky. They erected poles around the top perimeter, intricately connected them with ropes like a spiderweb, and then covered it with canvas. And who managed these hundreds of complex ropes? Not construction workers, but the navy. Sailors, who were accustomed to hoisting sails and battling the wind daily, were the experts at this sky-high roof. The idea of completely blocking out the sun, rather than just cooling the air, was truly remarkable.