Ancient strongholds are scattered over the county. Among the most remarkable are Vespasian's Camp, near Amesbury; Silbury Hill, the largest artificial mound in Europe, near Avebury; the mounds of Marlborough and Old Sarum; the "camps" of Battlesbury and Scratchbury, near Warminster; Yarnbury, to the north of Wylye, in good preservation; Casterley, on a ridgeway near Devizes; White Sheet hill; Chisbury, near Savernake; Sidbury, near Ludgershall; and Figsbury Ring, northeast of Salisbury. Ogbury, ten kilometres (6 mi) north of Salisbury, is an undoubted British enclosure. Durrington Walls, north of Amesbury, are probably the remains of a British village, and there are vestiges of others on Salisbury Plain and the Marlborough Downs.