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. 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.