Billionaire Bunker: Inside The World's Largest Private Apocalypse Shelter, The Oppidum

It stands alone in a quiet valley in the Czech Republic, bordered by a magnificent countryside. The estate is surrounded by high walls, and is not visible at ground level. From the air, the compound appears to be a large administration center. This is The Oppidum, a massive 323,000 square foot property with plans for a spectacular estate. What lies hidden beneath, carved deep in the mountain is the largest residential doomsday shelter in the world.