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 – including grey heron, little egret, cormorant, peregrine falcon, kingfisher, warblers and goldeneye. Designated a Site of Special Scientific Interest (SSSI), they form part of the Lee Valley RAMSAR Site (Wetland of Interational Importance). The ten reservoirs of Walthamstow Wetlands were built during the second half on the 19th century, in several stages, with work finishing in 1904. The Engine House, built in 1894, was in service until the 1980s – its ’swift tower’ replicates the original chimney (demolished in the 1960s) and includes 54 nesting holes for migratory swifts. Opened to the public in 2017 following significant investment in the site,  the wetlands are threaded with walking and cycling paths, and still act as the main water supply for around 3.5 million people.  I’m lucky enough to live just 5 minutes walk from one of the main entrances to the wetlands. You can view more images from Walthamstow Wetlands here.