River Fleet

The largest of London's lost rivers once ran openly from the high ground of Hampstead to the Thames at Blackfriars. - Status: Mostly culverted and buried beneath streets and sewers - Surface clues: The valley line still shapes routes through Camden, King's Cross, Farringdon, and Ludgate - Historical importance: The river gave its name to Fleet Street and helped define part of medieval London

Hampstead Heath to Blackfriars, London, United Kingdom