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
Canvey Island been discharged into the river by the means of seven sluices (later known as Commissioners Dykes). The completion of the work saw a considerable number of the Dutch engineers take land as payment for their work, and consequently settle on the island. Approximately one-third of Canvey's streets have names of Dutch origin. The coast of Canvey Island was host to the Chapman Lighthouse as briefly described in Joseph Conrad's novel "Heart of Darkness". It is believed that the peril of the mudflats below such shallow waters off the Canvey Island coast prompted the Romans to devise some form of beacon