The naumachia of Augustus in Rome, an artificial lake for staged naval battles
Can you picture a stadium in the middle of a city, filled with water and twelve times the size of Luzhniki? The ancient Romans could, and they passed their time at such a stadium very agreeably indeed.
Naumachia, from the ancient Greek for "naval battle", was a specially staged combat imitating a sea fight, and also the place where such a spectacle was held. This is very much what the naumachia of the Emperor Augustus in Rome looked like. The specially constructed lake for these battles is mentioned in the Res Gestae Divi Augusti ("The Deeds of the Divine Augustus"); the basin measured 550 by 360 metres, which allowed it to hold more than 30 ships and 3,000 men, not counting the rowers.