Walthamstow Wetlands in northeast London are one of the largest urban wetland areas in Europe, covering an area of 211 hectares, and providing an extraordinarily rich habitat for birds and other wildlife. The 10 reservoirs of Walthamstow Wetlands were built during the second half on the 19th century, with work finishing in 1904, and were opened to the public in 2017. A SSSI (Site of Special Scientific Interest), they form part of the Lee Valley RAMSAR Site (Wetland of Interational Importance), and as well as being a threaded with walking and cycling paths, they still act as the main water supply for aroud 3.5 million people.