Rome, Italy - In 1930 the Holy See, owner of the catacombs, entrusted the custody of the Catacombs of San Callisto to the Salesian Congregation. In the catacombs, divided into 4 levels, for a total extension of about 20 km, about 500,000 people were buried, including 16 Popes, Saint Cecilia and Saint Tarcisio. Saint Callisto was Pope and died a martyr.