Tower Ditch

TheTower Ditch, or Tower Moat, was part of the Tower of London’s medieval defences. It was built by the Bishop of Ely while King Richard I was crusading in the Holy Land (1187-1192) (Harben). The ditch was used as a dumping ground for plague victim corpses, human waste from the Tower, and meat carcasses from East Smithfield market.
On the Agas map, the ditch surrounds the Tower of London.

References