Northern section of land tunnel.
[Shaft of Ashokan Water Tunnel.]
[Subway tunnel.]
Railroad tunnels and bridge, south of Central Avenue.
[Man shaping a horseshoe.]
[McAdoo Tunnel.]
[Tunnel construction.]
Unidentified tunnel.
[North tunnel shield.]
[Constructing the McAdoo Tunnel.]
[Holland Tunnel.]
Unidentified track tunnel.
The Holland Tunnel
Southbound express tunnel.
[Streetcar tunnel.]
Bonticou Grade Tunnel Portal and Bonticou Crag [Catskill System.]
Queensboro Tunnel.