tunnel shaft
abri
access
adit
aisle
alley
ambulatory
antre
aperture
approach trench
arcade
artery
avenue
bore
bunker
burrow
cave
cavern
channel
cloister
colonnade
communication
communication trench
conduit
connection
corridor
couch
countermine
countersink
coupure
course
cove
covered way
covert
deepen
defile
delve
den
depress
dig
dig out
dike
ditch
dive
double sap
dredge
drift
drill
drive
duct
dugout
tunnelled
tunnelling
cut into
penetrate
perforate
turnover
tunneled
tunneling
tunnels
light at the end of the tunnel
tunnel vision
tunneller
wind tunnel
bridge
building
canal
canyon
chamber
dome
doorway
hole
lane
passage
pit
road
shaft
staircase
tube
valley
vault
Chunnel
Eurotunnel
chunnel
funnel
gangway