These air raid shelters in Manchester, UK have been abandoned since the end of World War II. Which is probably why Exploring with Fighters were so excited to see what was down there, if anything. Would they find treasure, ghosts, a cardboard cutout of Finn from Star Wars? Actually, that last one they did find. It's an amazing journey through a series of tunnels that haven't been used in over half a century. 

Check out the full video on their YouTube page.