Over the centuries, the entire world tried to figure out the origin of Fosse Dionne’s waters in central France.
Ancients believed that they were derived from the lair a serpent-king. Some believed there was an exit to another dimension at the base the spring.
In the decades 1974-1996, two courageous divers drowned trying to find the answer.
In the Burgundy wine country, the mysterious Fosse Dionne Spring (pictured) can be found in Tonnerre.
The full answer as to what lies at the base of the spring remains elusive, and it’s this enigma that keeps tourists visiting the spring every year
Dye tracing studies have intimated that some of the spring’s water comes from an underground section of the Laigne River, which flows above ground 27 miles (43.5 kilometres) from Tonnerre
Yet still, the full answer as to what lies at the base of the spring remains elusive, and it’s this enigma that keeps tourists visiting the spring every year.
The spring is set in the pretty pastel-coloured town of Tonnerre in Burgundy, through which the River Armancon flows – and spews out more than 300 litres of water per second – that’s enough to fill three standard bathtubs.
Floodwaters can flow out at more than 3,000 litres per second during times of flooding.
In the 18th century, French nobles built a wash house or ‘lavoir’ around the spring and this stone structure still surrounds the waters today
Even from the surface, the waters of Fosse Dionne seem deep. An ancient belief held that the Fosse Dionne had a portal into another world.
You can explore the old washhouse buildings and peer into the blue green waters to find out the source of the spring.
The oldest written references to the spring can be traced back to the 7th century and it’s known that the Romans used its waters for drinking.
In the 18th century, French nobles built a washhouse or ‘lavoir’ around the spring and this stone structure still surrounds the waters today.
The spring is open to visitors who wish to explore its historical buildings and gaze into the waters.
The buildings shown here are located on Tonnerre’s banks.
The spring spews out more than 300 litres of water per second – that’s enough to fill three standard bathtubs – and up to 3,000 litres per second during flooding
Scientists have conducted many experiments on the spring over the years to determine its origins.
Dye tracing studies have intimated that some of the spring’s water comes from an underground section of the Laigne River, which flows above ground 27 miles (43.5 kilometres) from Tonnerre.
The most daring investigation of recent years, however, was carried out in 2019, when diver Pierre-Eric Deseigne was given permission from Tonnerre’s mayor to explore the dangerous passageways beneath the spring.
After ascending 70 metres below the ground and exploring tunnels and caves for 370 meters (1,213 feet), he could not confirm where the spring came from.
It is still the secret to the water.