The catacombs are underground tombs which are located not far from Rome, where the old Christians are buried. These tombs are carved into the soft rock of the sacred area surrounding Rome.
When Emperor Nero began to persecute the Christians, they were gathered in prayer at the tombs. In the catacombs, every citizen was safe. Later, in the mid third century, even the catacombs were no longer safe. Christians then bricked up the existing entrance and made new secret underground passages that went for miles. It says that the catacombs were longer than the Apennine Peninsula to provide linear corridors!
When, in the time of Constantine, ended the persecution of Christians, the catacombs are visited by many pilgrims. When the Goths 410 occupied and sacked Rome, enters to the catacombs were buried to protect them. Already in the 12th century, catacombs were completely forgotten. They were so well hidden that one catacomb was accidentally found in 1578th.
The corridors in the catacombs are usually linear and long 3-4 km. They’re wide just enough to get two undertakers, who carry bier, can pass each other. The stairs leading into the hallways are 12 meters below ground. At the bottom of the stairs, corridors branch off in all directions.
Some of catacombs have two more levels. For example catacombs of St. Sebastian have four levels. The walls of the catacombs are located in a cavity which was placed in the body of the dead. These cavities were originally walled with brick or stone. Many of these partitions are meanwhile loosened and cracked, so today’s catacombs visitors have to squeeze between the long rows of skeletons.