underground tunnels
Subterranean transit routes
Underground tunnels are passages excavated beneath the earth's surface.
The phrase emphasizes concealment or secrecy—smugglers use underground tunnels, prisoners escape through them, resistance movements build them.
When tunnels appears alone, the underground location is usually implicit; the full phrase stresses the hidden nature: They discovered a network of underground tunnels beneath the border.
- catacombsUnderground cemetery passages
- secret passageConcealed route through structure
- metro systemsUrban underground railways
- subway systemUrban underground rail network
- escape routesPlanned paths for evacuation
subterranean · excavation · dig site · bedrock · sewage systems · storm drain · folklore legends · ventilation · archaeological sites · ancient aqueducts · speakeasy · rat run · clandestine · reinforcement · mining shafts · coal mine · bunkers · bomb shelter
- falaj irrigationmain channel, distribution channels, sluice gates, water clock
- campus featureslibrary, libraries, dorm, dorms, dormitory
- NurembergNuremberg Trials, Nuremberg Laws, city walls, medieval walls, bratwurst
- labyrinth elementsmazes, dead ends, hedge mazes, spiral stairs, secret passages
- Metrosubway, metro, tube, underground, station
underground tunnelsoverpasses
Elevated road crossings
skyways · suspension bridges · elevated railways · sky bridges · viaducts