A team of scientific experts have explored a recently discovered complex of underground water tunnels for possibly the first time in centuries near Sevilla.
The five speleologists dedicated to the scientific study of underground spaces are all experts in their field, but the video is not for the claustrophobic or katsaridaphobic (fear of cockroaches) – so anybody who is worried about insects should avoid watching from the 30 to 50 second mark.
The Roman-era galleries were recently discovered during road construction works in the historic town of Carmona situated around 30 kms from Sevilla.
Jose Naranjo, president of the Andalusian Association of Underground Exploration, told Real Press in an interview: “A well was discovered which connected with one of many galleries to collect water.”
He added: “They are of Roman origin.”
Before exploring the dangerous and incredibly tight space, the speleology team used remote cameras and specialised equipment to examine the galleries and confirm they were safe to enter.
Naranjo believes they date back to the 1st Century AD when they were built to collect and distribute water across the city, especially to water-hungry agricultural and milling facilities used in those times by the populace.
He said: “Under Carmona it is full of underground natural springs, and Romans built this structure to collect the water from them and channel it to the places where it could be used.”
The galleries still serve Carmona in some parts of the outskirts as they provide water to fountains, according to Naranjo.
But, he said, this newly found gallery complex has not been explored by anyone in centuries, though it is possible that some restorations and repairs were done in the Middle Ages between 1400 and 1600.
The 100-metre-long (109 yard) gallery section explored in this video is dug into stone, allowing for stalagmites to eventually form, but much of the complex is through soft earth and its Roman architects needed strong structural reinforcements to prevent collapse.
Naranjo said: “Romans were experts in big constructions, like aqueducts, and these mines (as the galleries are called) are built using more or less the same construction techniques.”
He added: “The Roman construction system consisted in digging vertical wells, and those wells were joined in horizontal galleries with a small slope so that the water could not flow too fast while collecting the water from underground.
“So, it was a collection system, but also an aqueduct.”
But, he said, some parts of the galleries needed special attention: “When the ground is soft, they had to use bricks or stones to build a kind of vault so that it did not collapse.”
The materials used to build those vaults helped speleologists confirm that the galleries dated back to the Roman empire, as well as the fact that they supplied water to buildings known to have Roman origins.
The team faced difficulties in some gallery sections where flooding meant they had to use pumps to remove the water before entering and rock falls sometimes prevented access.
But Naranjo said there are still a lot of galleries to explore, and they will keep working on it with support from the city council and local archaeological services.
Carmona, known in Roman times as Carmo, was conquered by the Roman empire in 206 BC. Its strategic location meant it was considered an important city, remaining so through the Moorish period until the Middle Ages.
Naranjo believes many more Roman era galleries are to be found beneath the city and though his team has so far explored nine kilometres (5.5 miles) of them, many more remain to be documented.