The theatrical genre of aqua drama that was popular in 19th century France, England, and the United States involved flooding the arenas of circuses for recreations of major naval conflicts and similar aquatic events; some venues participated to such a great extent in this once-popular form as to install permanent water-tanks on stage. Water-based spectacles, especially those portraying great naval battles, had been popular in Roman times, when they were known as naumachia, and the custom was resurrected at various times during the Middle Ages.