Database: Porta Metronia

Built in conjunction with the Mura Aureliane (Aurelian Walls), the Porta Metronia was sealed at the end of the Middle Ages, allowing Pope Callixtus II to create a small channel through it for the Acqua Mariana, a river whose stagnant waters would later cause an outbreak in 1601.

Good deed + passage of time = plague. That's the circle of life.