Tunnels for motor vehicles:
Railroad tunnels:
Metro tunnels:
Light-rail tunnels:
Also there are pedestrian tunnels in many train stations.
... related[?] Amyloidosis of gingiva and conjunctiva mental retardation[?] Amyloidosis, Familial[?] Amyloidosis[?] Amylopectinosis[?] Amyoplasia mandibulofacial ...