11. The Leaning Tower of Bridgnorth - Bridgnorth, Shropshire

All that is left of Bridgnorth Castle is the 70-foot Norman tower. The team are in the park, trying to piece together what it looked like in its heyday, 900 years ago. They must dig outside the area of the scheduled monument. Phil and a group of enthusiasts recreate a 12th-century catapult known as a perrier. They are joined by castle specialist Philip Dixon, Mark Horton from Bristol University, Small Finds expert Lynne Bevan, and pupils from nearby Oldbury Wells School. Finally Philip is able to describe the construction and layout of the castle.