Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. They say all roads lead to Rome. But in the Eternal City, all of the major roads were thought to lead somewhere very specific—a single column called the Milliarium Auereum, or the golden milestone. It doesn’t feel like a coincidence that Emperor Vespasian (9–79 CE) started building the Colosseum so close to the Milliarium Auereum. After all, it is where Roman emperors brought the world to their people, Alexander Mariotti, a gladiatorial historian at the British Institute of Roman History, tells Popular Science.  “Romans wouldn’t go to North Africa or India or even the forest of Germany,” Mariotti explains, “but you didn’t need to, in the same way that one can sit on a couch and watch YouTube, but not necessarily need to travel because the world is brought to you. Well, the Roman emperors brought the world to Rome for them to see.” Vespasian did not live to see the completed Flavian Amphitheater, as the Colosseum was originally …