Though urban legend has it being the only man-made object visible from space this one part is lying up to 100 feet below a valley flooded when a dam was built.
Mr Meur, the expedition photographer, said just getting the 500kg of equipment down hundreds of steps to the water's edge was a challenge in itself.
"The lake itself is rather barren, with only a couple of species of freshwater fish and shrimps," he said.
"The real stars here really are the ruins. The wall is in amazingly good condition considering that it is several hundred years old, and is underwater.
"The top of it was at around 13m depth, and we located a guard tower, with openings on all sides, which created underwater tunnels."
He added: "Throughout the dives, the weight of history was very present on our minds. It was incredible to navigate the wall and guard posts, thinking that centuries ago soldiers were walking the same location, keeping China safe from intruders."
"We did two dives on the Wall and wanted to do more but were plagued by technical problems.
"The diving was challenging as it was 25 centigrade on the surface but dropped to just six degrees when you got 35 metres down on the bottom.
"Visibility was limited to about 1-5 metres maximum, as the bottom is very silty. If you stir the bottom, you end up diving in soup."
The parts of the wall that are best known date from the mid 16th century, although the first great wall was ordered to be built in 214 BC.
The most comprehensive archaeological survey, using advanced technologies, has recently concluded that the entire Great Wall, with all of its branches, stretches for 8,851.8 km (5,500.3 miles).
This is made up of 6,259.6 km (3,889.5 miles) of sections of actual wall, 359.7 km (223.5 miles) of trenches and 2,232.5 km (1,387.2 miles) of natural defensive barriers such as hills and rivers.
Panjiakou reservoir was created in 1977 during the grip of the cultural revolution when the valley near Tangshan was flooded, submerging a village and wall to create a dam.
http://www.telegraph.co.uk/news/worldnews/asia/china/7714060/Ghostly-pictures-of-Great-Wall-of-China-taken-from-underwater.html