Since prehistory, bunkers have been built as protection from cataclysmic social and environmental forces, and as places of power and transformation. Today, the bunker has become the extreme expression of our greatest fears: from pandemics to climate change and nuclear war. And once you look, it doesn't take long to start seeing bunkers everywhere. Acclaimed urban explorer and cultural geographer Bradley Garrett explores the global and rapidly growing movement of 'prepping' for social and environmental collapse, or 'Doomsday'.