A few traces of the Roman city remain visible, such as parts of the city walls, a hypocaust – still "in situ" under a mosaic floor, and the theatre, which is on land belonging to the Earl of Verulam, as well as items in the museum. Further remains beneath nearby agricultural land have only had a few exploratory trenches, have never been fully excavated and were, for a while, seriously threatened by deep ploughing, which ceased in 2005 after compensation was agreed. Test trenches in 2003 confirmed that serious damage had occurred to buildings on the northern side of Old Watling Street by deep ploughing. Permission needs to be granted to enable the full extent of the damage to the western half of Verulamium to be investigated.