When the Colosseum was flooded so that the Romans could watch a mock naval battle

The first naval battle staged in the Colosseum was held in 80 AD, during the inauguration of the Flavian Amphitheatre.

The event was organized by the Emperor Titus, and involved over 3,000 men and a large number of ships.

The spectacle was so popular that it was repeated several times over the years, with the last recorded naval battle taking place in 107 AD.

The naval battles in the Colosseum were typically staged during the midday interval of a day of games.

The floor of the arena was filled with water, and elaborate sets were constructed to recreate various maritime scenes, such as ports, islands, and even entire cities.

The ships used in the battles were often scaled-down versions of real warships, and were manned by prisoners, slaves, or criminals who had been sentenced to death.

The battles themselves were often highly choreographed, with the ships engaging in mock naval warfare using weapons such as grappling hooks, catapults, and ballistae.

The audience would be seated around the lake, and would watch as the ships collided and sank, while soldiers and gladiators fought to the death on the decks.