This video covers Undercities and Domes. It also covers Anihilatronic weapons which are the in-universe equivalent of nuclear weapons. The concept of the Undercity is influenced by the novel 'Domain' by James Herbert. The concept of the Dome comes from the 2mm scale Dome made by Irregular Miniatures in their science fiction 2mm range, as well as the dome city in 'Blake's Seven' (the first episode), and the idea of a 'pleasure dome' from Frankie goes to Hollywood.