The most famous (and perhaps the most impressive) catacombs in the world are found in and around Rome. Many tours of the catacombs of Rome trace the city's colorful and sometimes-violent history from medieval times back to the first year of the Common Era. These are the catacombs of lore, with their stacked skulls and human bones laid out in unusual patterns. Tours from companies like Dark Rome offer stops in multiple catacombs including some of the most famous, including San Sebastian and the Capuchin Crypt. Roman tour companies also visit archeological sites like the Basilica of San Clemente, where ancient worship spaces and Roman ruins were discovered in layers below the tiles of the church.