This 12,000-year-old massive underground network is very impressive. Some experts believe the network was a way of protecting man from predators.

Others suggest the linked tunnels were used as an ancient underground superhighway for people to travel safely regardless of wars, violence, or even weather above ground.

Since at least 2011, web sites dedicated to spreading rumors about spirits and the underworld have been claiming that a connected “network” of tunnels dating back to the Stone Age and stretching across Europe from Scotland to Turkey has been discovered.

They could be described as a kind of ancient underground superhighway. Others think the tunnels can be seen as a gateway to the underworld.

German archaeologist Dr. Heinrich Kusch said evidence of the tunnels has been found under hundreds of Neolithic settlements all over the continent. In his book – Secrets Of The Underground Door To An Ancient World (German title: Tore zur Unterwelt) – he says that the fact so many have survived after 12,000 years shows that the original tunnel network must have been enormous.

“In Bavaria in Germany alone we have found 700metres of these underground tunnel networks. In Styria in Austria we have found 350metres,” he said.

Evidence of Stone Age tunnels has been found under hundreds of Neolithic settlements all over Europe – the fact that so many have survived after 12,000 years shows the original tunnel network must have been huge

“Across Europe, there were thousands of them – from the north in Scotland down to the Mediterranean.

Most are not much larger than big wormholes – just 70cm wide – just wide enough for a person to wriggle along but nothing else.

They are interspersed with nooks, at some places it’s larger and there is seating, or storage chambers and rooms. They do not all link up but taken together it is a massive underground network.”

Not for the claustrophobic: Most of the tunnels are just 70cm wide – just wide enough for a person to slowly wriggle through

In his book, he book notes that chapels were often built by the entrances perhaps because the Church was afraid of the heathen legacy the tunnels might have represented and wanted to negate their influence.

Similar underground tunnels exist on other continents. Throughout all the Americas there are a number of legends of the secret of subterranean passages stretching for miles.

Were these tunnels made by giants or did perhaps our ancestors for some reason seek protection underground?

Many of these ancient legends tell of a great catastrophe that occurred in ancient times. Several myths and legends also relate to how the first human beings emerged from underground caves, tunnels, and even cities.