underpass, viaduct, passageway, cavern, trench, corridor, tramway, pedestrian bridge, walkway, bridge, overpass, channel tunnel, underground, tram, rail, shaft, expressway, manhole, verrazano narrows, travelator, archway, stadium, footbridge, underbridge, bascule bridge, corn borer moth, stairway, chunnel, snowshed, pipe, mousehole, aerotrain, mineshaft, ventilation shaft, falsework, gondola, cave, flume, freeway, toll plaza, roadbed, bailey bridge, skyway, subway station, culvert, monorail, skywalk, autopista, transalpine, trestle bridge, tacoma narrows bridge, trestles, turnstile, staircase, pier, aqueduct, floating bridge, rush hour, railway, gasometer, canal, excavation, highway, overcrossing, tramline, girders, concourse, millrace, pylon, penstock, bosporus bridge, breakwater, offramp, crossway, subway, headrace, rockface, peristyle, spaghetti junction, gates, causeway, cloverleafs, particle accelerator, elevator shaft, aerial tramway, dome, lanes, motorway, guideway, maglev, stairwell, ropeway, outfall, elevator, manway, retaining wall, truss bridge, gantry, hole, donner pass, lightrail, arches, tunnels, chute, canyon, chamber, bunker, hallway, hangar, square, cage, cellar, thermionic, cavity, emitter, absorption, acceptor, antiparallel, apollonian, assimilative, associationist, augustan, balzacian, beehive, bias, block, brechtian, bridged, bursty, chaucerian, christocentric, circuit

catacomb, rabbit warren, railroad tunnel, warren

carpal, carpal tunnel syndrome, catacomb, channel tunnel, chunnel, conduit, countermine, drive, hazmat, railroad tunnel, subway, underpass, wind tunnel

cut into, delve, dig, hollow, penetrate, turn over

burrow