sentences:  Because of this, the fourth series saw the introduction of many 'outdoor' scenes, filmed around places such as medieval castles across the UK, and composited into the blue room using the usual chromakey technique.This series also saw the introduction of the "Eye Shield", which acted as an 'eye' for the dungeoneer.Using pre-recorded footage filmed on location, it followed the progress of the dungeoneers as they explored the dungeon.