Dozens of underground “catacombs” surrounded Rome in ancient times, when people were buried outside of town. Pagans were fine with cremation, but Christians, believing that the Second Coming was just around the corner (and thinking a body might come in handy), preferred a burial. Most Christians couldn’t afford standard plots — but a few were wealthy, and they gave their fellow Christians access to any underground necropolis they wanted to dig. The volcanic stone was easy to tunnel and dig into,