Exploring Old Byron Hot Springs in the Californian desert - a once glittering Hollywood hotspot, converted into a top-secret interrogation centre.

Yongma Land is a South Korean dreamland given a second life from the most unlikely of places; Saguramo Space Research Centre is a state-of-the-art facility that thrust the Georgian nation into the world's greatest race; Donnottar Castle is an ancient Scottish fortress besieged by a warrior that would inspire a Hollywood epic; and Nis Concentration Camp is a Balkan house of horrors that symbolised the worst of humanity.