The phrase: “We who are about to die salute you,”was not as commonly used in Ancient Rome as the media likes to portray. In fact, the only known case when the saying took place is during Emperor Claudius’s naumachia- a fierce naval battle staged in the middle of a real lake for the purpose of entertainment. Read more
Originally the Colosseum’s floor could be removed within a short amount of time to make the ground deeper than usual. Then it could be filled with water for boats to sail in it, so naval battles could be arranged. Water was drained off from nearby aqueducts and could fill the arena within the very same day as the land fights happened. Read more