From the site:
"The Great Dune of Pyla is the tallest sand dune in Europe. It is located in the Arcachon Bay area, France, 37 miles (60 km) from Bordeaux.
The dune has a volume of about 60,000,000 m³, measuring around 1,640 ft (500 m) wide from east to west and 1,9 miles (3 km) in length from north to south. Its height is 350 feet (107 metres) above sea level."