Along the north bank of the Thames, downstream from Tilbury , is where London's rubbish ended up. Just past the power station is Bottle Beach, where the remains of a (Victorian?) dump are exposed by the river. Bottles, glass and china survives, but most of everything else has decomposed. Even the metal has rusted away.
The 'water tower' was an early radar station, and according to to font of all knowledge was, until recently, still marked as a water tower on maps.
A proper walk, even if it was across crushed and broken glass :-)