I hadn’t heard about this before. I watch archaeology shows like Time Team and Cities of the Underworld regularly. I’m surprised they haven’t mentioned this on the shows I’ve seen.
I wonder if these were dug to avoid predators like bears, and leopards & jaguars? I can’t imagine digging these with stone age tools.
http://au.news.yahoo.com/thewest/a/-/offbeat/9979541/tunnels-were-freeways-of-stone-age-world/
Perhaps, or maybe to hide from other people bent on rapine and pillage.
Bookfinder.com only found this guys book in German, published 2009. No English versions under this authors name.
Author is Heinrich Kusch
Title is Tore zur Unterwelt
Book is written in German
Doesn’t do me much good. 
I would have enjoyed reading it.
“Behold the Underminer! I am always beneath you, but nothing is beneath me! I hereby declare war on peace and happiness! Soon all will tremble before me!”
That’s obviously the Underground Railway. A Neolithic Chunnel.
Did they find a Horta?
Heh. The Austrian link says:
Some experts believe the network was a way of protecting man from predators while others believe some of the linked tunnels were used like motorways are today.
The Yahoo link Americanizes it to:
…others believe that some of the linked tunnels were used like freeways are today.
But either way, the image of thousands of real-life Fred Flintstones commuting through dark two-foot wide passages is pretty funny.
I can’t believe that a tunnel would have any advantage over a ground-level pathway for long-distance travel other than protection from predators, especially since you’d need some kind of lighting all the time you are in the tunnel. One big problem would be tunnels under rivers and wetlands: how would you keep them dry without some kind of pumping system? I can understand them being used for other purposes, e.g., sleeping and storage, but for travel they make no sense.
There was a longer article about these tunnels, called Erdställe (singular: Erdstall) in the German magazine Spiegel recently. It is also available in English:
They don’t give a lot of credence to that author Kusch and his theories of neolithic underground networks. The tunnels rather seem to stem from the middle ages or the migration period before, and there is also little evidence for large networks, but only isolated and relatively short tunnels. Still, their exact origin and purpose remain pretty mysterious.
The idea that they may have been hideouts or hidden storage places is also discussed, but there are some arguments against it: They are pretty impractical for those purposes, too narrow to move around in them easily, and the supply of oxygen would quickly become a problem. There also are hardly any traces of supplies having been stored in the tunnels. So instead, they speculate about some religious functions.
Literal Man Caves.
A freeway? Did you see the dude squirming thru that tight hole? (Insert joke here)
We’ve got many kilometers of underground passages just like that in Kentucky, Tennesee, Missouri and Arkansas as well as many other US states.
We call them “caves.” They were made by flowing underground water over millions of years, not aliens, not religious fanatics, and not prehistoric stoneage Homo sapiens. They are 100% natural and so far, Kentucky isn’t claiming they were used as freeways.
If you don’t believe me, ask any geologist about karst country.
Oh yeah? Then how do you explain the graffiti, “Klaytu sucks”, hmmm?
Time travelers.
Sometimes the tunnels were the Medieval equivalent of a panic room. There’s a good example in northern France.
Heh. Don’t archaeologists always assume some religious function if they don’t know what something is for?
Great article. Thanks for posting the link. 
Amazing how many theories there are about these tunnels. They don’t seem big enough for any practical use.
Those Stone-agers just never cease to amaze.
Yeah, the aging Stones just keep on rockin’.