The tunnels at Cricova were made when people cut out big blocks of limestone to use for building houses above ground. Over many years, this left behind an enormous maze of corridors — wide enough for two cars to pass each other and tall enough to stand in comfortably. The temperature inside stays cool and steady all year round, no matter how hot or cold it is outside.
The underground streets are given names just like real city streets above ground. There are intersections, turnings, and even small squares where corridors meet. If you walked down every single tunnel without stopping, you would be walking for the same distance as a journey from one side of Luxembourg to the other.
The rock walls glow a warm cream-white colour when lights shine on them, making the tunnels feel almost magical. Some sections have high curved ceilings that make your voice echo. People from all over the world come to marvel at how something so big and interesting can be hidden completely out of sight beneath ordinary hills.
Because the underground temperature never changes, the tunnels create a perfectly still, quiet world. The air is fresh and cool even in summer. Children who visit often say it is like being inside a giant ant nest — but with paved roads and electric lights.