The Romans were famous for their engineering prowess in building structures like bridges, aqueducts, amphitheaters, and even tunnels. Under the reign of Emperor Claudius, the Romans built the longest tunnels of the ancient world up until the Frejus Rail Tunnel in 1871.

Not far from the tunnels is Rome, and in Rome, one can see the original Roman catacombs where the Christians hid and buried their dead. The Romans have left marvels of engineering both above and below the ground. In Paris, the famous quarries under the city were started by the Romans and today around 6 million people are buried in them.


Background and History of the Tunnels of Claudius

The tunnels enabled the Romans to protect the human settlement along the lake from flooding and make former wetlands suitable for farming.

  • Length: Nearly 6 KM (3.5 Miles)
  • Listed: In 1902 The Tunnels and Hydraulic Work Was Included In The Italian National Monuments

The petitions for the imperial Roman authorities to do something about the flooding of the lake date back to the reign of Julius Caesar. The inhabitants suffered from poor sanitary problems from the flooding. A plan was drawn up to fix the problem and to connect the River Tiber with the Adriatic Sea, but with the assassination of Julius Caesar, that plan was stalled.

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Years later another plan was created. This called for the digging of a canal so that the water could flow out through the Cesolino hill and then empty into the River Salto. But this too was scrapped for fears that it would increase the risk of flooding in the city of Rome downstream.

  • Built By: Emperor Claudius

But third time's a charm and the solution was to divert the waters through a tunnel through Mount Salviano into the River Liri. This plan was much more difficult but posed no problem for Rome.

The project took 11 years to complete and involved around 30,000 men digging (some were slaves). Unsurprisingly the project ran into many problems including landslides but the Romans perseverated and persisted.

  • Date Built: Between 41 and 52 AD

According to I, Claudius, in celebration of its completion, Emperor Claudius held a public festival with a staged naval battle on the lake. The locks were opened by Claudius for the very first time. In the crowd, that day was Claudius's young relative Nero (who would go on to become the infamous Emperor Nero).

  • Drained: 6,000 Acres of Fucine Lake

The Tunnels of Claudius are made up of a long underground canal, six inclined service tunnels, and 32 wells. They were built to control the levels of Fucine Lake in Abruzzo and to protect the surrounding land from floods and increase land available for cultivation.

As a result of the tunnels, the lake basin shrank by 6,000 acres and the risk of flooding significantly eased.

Related: Visiting The Creepy Znojmo Catacombs In The Czech Republic

Decline Of The Tunnels

As the Western Roman Empire declined the main canal was not maintained after the ensuing Barbarian invasions. Over time it became clogged and from 1854 a new canal was built.

Additionally, an earthquake in 508 AD probably damaged the system and the levels of the Fucine Lake returned to what they were before the tunnel drainage system was built.

Over the years there were some failed attempts to restore the system (including an attempt by Frederick II of Hohenstaufen in the 1200s). But restoration attempts were plagued by the lack of funds and a lack of understanding of the complexity of the project.

  • New Drainage Project: Completed in 1870

In the 1800s Prince Alessandro Torlonia of Civitella-Cesi ordered the construction of new hydraulic works. This proved successful and it resulted in a 6-kilometer long drainage canal largely following Claudius’ immisary and emissary.

From 1875 to 1876 the 16,000 hectares of Lake Abruzzese (Italy's third-largest lake) were completely drained. It was officially declared drained on 1 October 1878. The resulting Fucine plain proved great for growing cereals, vegetables, and sugar beets, and many of the former fishermen became farmers.

Related: These Are Some Of The Best Preserved Roman Roads To Explore

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The Tunnels And Visiting Them Today

The tunnels are considered to be one of the grandest hydraulic works of engineering in antiquity. For 1800 years it was the longest tunnel ever built until the opening of the Fréjus Rail Tunnel.

  • Fréjus Rail Tunnel: Runs Through Mon Cenis In the Alps To Connect The Railways Between Paris and Rome

Today the tunnels are part of the Archaeological Park of Claudius formed in 1977 to protect them. Unfortunately, while one can visit the tunnel entrances but the tunnels themselves are blocked off and not open to the public at the moment.

  • Visiting: No Open To The Public (The Entrances Can Be Seen)

One visitor to the site remarked on Google Reviews:

"Amazing Roman Engineering and construction. Sad to see it utterly abandoned and in a sorry state. Could easily be a fascinating archeological site."

 Next: See The Ancient Roman Catacombs Of Kom El Shoqafa In Egypt