Stone Age Tunnels
In Bavaria alone, there are a whopping 2296 feet of underground tunnel networks. Across Europe there were thousands running from the Scotland to the Mediterranean. Most are were not much larger than 70cm wide, but some sections even contain seating, storage chambers or rooms. Amazingly, some of these tunnels date back over 12,000 years. Some experts believe the network was a way of protecting man from predators, while others believe that some of the linked tunnels were used for people to travel safely regardless of wars or even weather above ground.