of San Callisto. If you are interested in Roman and religious history, then this is

a place you can't skip. The size of the catacombs is stunning. The

tunnel complex stretches out for almost 19 kilometers and is structured in five levels.

The deepest parts of the catacombs reach an impressive depth of roughly 20 meters.

The history of these catacombs dates back almost 2000 years. The original catacombs

are believed to have been a private Christian underground burial place. The reason for it

being underground was because Christians, prior to Emperor Constantine the 1st were

often persecuted for their religious beliefs. In fact, the government of Rome persecuted

all those who chose not to practice the religion of the state. During these times, the Christian

religion was not as dominating as it is today which forced the Christians to literally hide

underground. The underground cemetery was expanded during

the end of the 2nd century by a deacon of Rome. The catacombs were expanded to not just

include more tombs, but also chapels, meeting areas, dining rooms and even places to sleep.

The man responsible for the expansion later became a Pope under the name Callixtus the

1st. As you probably guessed, the name of the catacombs -- San Callisto - derives from

this man. Sometimes they even go by the name of Catacombs of St. Callixtus.

After the expansion, the catacombs quickly became the official burial site for Rome's

Christians which was followed by additional expansions. Over the course of history, more

than 50 martyrs and 16 popes have been buried here, making it one of the most important

Christian cemeteries, if not the most important.

The catacombs were rediscovered by the Italian archeologist Giovanni Battista in 1854. When

he discovered the tunnels, he called them "the little Vatican - the central monument

of all Christian cemeteries". After you've visited the catacombs, I'm sure you can see

why he used grand words like these. Inside the underground complex, you can discover

the Crypt of the Popes and investigate the crypt of St. Cecilia - the patron of sacred

music. You can also find several ancient frescoes, sculptures and other wall paintings along

the impressive tunnels. The catacombs are truly an example of great underground architecture.

These catacombs are the most visited ones of all the ancient underground tunnels in

the region. Tens of thousands of people visit the site each year to experience the phenomenal

tunnels.