Odesa Catacombs

Beneath and around Odesa lies an enormous labyrinth of tunnels, among the longest such networks in the world, formed mostly by centuries of quarrying the soft local limestone used to build the city above. Cool and dark, the passages were used by smugglers and later by partisans who sheltered underground in wartime. Part of the system near the outskirts is open as a museum, where guided tours explain the quarrying, the resistance history and the geology.