Grim's Ditch (Harrow)

Grim's Ditch or Grim's Dyke or Grimes Dike is a linear earthwork in the London Borough of Harrow, in the historic county of Middlesex, and lends its name to the gentle escarpment it crowns, marking Hertfordshire's border. Thought to have been built by the Catuvellauni tribe as a defence against the Romans, it extended east–west about 6 miles (9.7 km) from the edge of Stanmore where an elevated neighbourhood of London, Stanmore Hill, adjoins Bushey Heath to the far north of Pinner Green – Cuckoo Hill. Today the remaining earthworks start mid-way at Harrow Weald Common.