Gladiator.

Picture this: You're about to march through the amphitheater's stone arches to face 30,000 screaming, blood-lusting brutes. Spittle and curses fly from toothless jaws while the dirt floor already clumped into obscure pellets stained dusty burgundy.

Nervous? Need fast relief?

Asking yourself, "While in the bowels of the arena before a brutal contest, where did the Romans crap?"

Answer:

Disclaimer: This amphitheater was actually used for opera.