Rome has its famous catacombs and so does Paris. But the city with the largest network of underground tunnels is undoubtedly Odessa, Ukraine.
Its 2,500 kilometers eclipses the 300 kilometers found in Rome and the 500 kilometers in Paris. Get lost here and you’ll be eating rats until you die a dark lonely death.
The catacombs were mostly created during the construction of the city as early engineers mined them for construction material. They were used for various nefarious purposes over the years and as a base for partisans during World War II.
Today, a small portion of the tunnels remain open to the public as a museum dedicated to the partisan efforts. I toured it myself a few years ago and wasn’t too wildly impressed. The museum wound through a short section of the tunnels and was strictly average with some random WW II weapons stuffed into cubbyholes and dummies dressed up in partisan costumes.
The remaining 2,499 kilometers, however, remain an alluring attraction if you can ditch the tour and find your way in. Bring plenty of bread crumbs to find your way out, however.