River Thames shipping coming in and out of London, in 1732 it received the world's first lightship. This became a major landmark, and was used as an assembly point for shipping. Today it is marked by Sea Reach No. 1 Buoy. The River Thames contains over 80 islands ranging from the large estuarial marshlands of the Isle of Sheppey and Canvey Island to small tree-covered islets like Rose Isle in Oxfordshire and Headpile Eyot in Berkshire. They are found all the way from the Isle of Sheppey in Kent to Fiddler's Island in Oxfordshire. Some of the largest inland islands, for example
Dee Estuary channel which it cut through the base of the Wirral Peninsula. The estuary is a major wildlife area and one of the most important estuaries in Britain, amongst the most important in Europe for its populations of waders and wildfowl. The Environment Agency is the Conservation Authority, and the estuary is protected or listed under several schemes: Large parts of the area are within the RSPB's Dee Estuary Nature Reserve. The estuary supports some important natural fisheries, including salmon and trout on their way to and from the freshwater river, as well as sea-fisheries and shell-fisheries, especially cockles. From earliest