Durdle Door is a natural limestone arch on the Jurassic Coast near Lulworth in Dorset, England. It is privately owned by the Welds, a family who own 12,000 acres (50 km2) in Dorset in the name of the Lulworth Estate. It is open to the public. The name Durdle is derived from an Old English word 'thirl' meaning bore or drill.
