Armed with laser rangefinders, GPS technology and remote control robots, a group of speleologists is completing the first ever mapping of the aqueducts of ancient Rome on archaeology's "final frontier."
They abseil down access wells and clamber through crevices to access the 11 aqueducts that supplied Rome, which still run for hundreds of kilometers (miles) underground and along stunning viaducts. The mission of these "speleo-archaeologists" is to update the last above-ground map of the network compiled at the beginning of the 20th century by British Roman archaeologist Thomas Ashby. As he made his way through a perfectly preserved tunnel section of the Acqua Claudia on the grounds of a Franciscan convent in Vicovaro near Rome, Alfonso Diaz Boj said he was "proud" of the study.
"It combines what was the birth of archaeology as a science with the latest instruments available," said Diaz Boj, a member of Sotterranei di Roma (Underground Rome), in a hard hat and torch.
The pick marks of the Roman diggers can still be seen in the limestone of the tunnel completed in 38 AD under the Emperor Claudius and a lawyer of calcification about half a meter off the ground shows where the water level would have been.
"These aqueducts may not be as beautiful as a statue or like some architecture but I think they are important, they are very beautiful," he said.
The ancient waterways were true feats of engineering, which relied solely on gravity to ensure a flow of water can be seen across what was once the Roman Empire from Germany to North Africa.
Their strategic significance is underlined by the fact that Rome had a special magistrate to oversee their maintenance and that the Visigoths cut them off when they were laying siege to the city. The Acqua Claudia runs 87 kilometers (54 miles) from the Simbruini Mountains to the heart of Rome and supplied 2,200 liters of water a second.
Only one of the aqueducts is still operational today -- the Acqua Vergine -- which can be accessed in various hidden locations near Rome including a doorway near the Villa Medici that leads down a spiral staircase to the water. The Acqua Vergine runs for a total of 20 kilometers and ends up in the Trevi Fountain, photographed every day by crowds of tourists.