does the tunnel (mentioned at the beginning) consists of tubes?
Yes, a pair of tubes
Holland Tunnel
It consists of a pair of tubes with diameters, running roughly parallel to each other and apart underneath the Hudson River. The exteriors of each tube are composed of a series of cast iron rings, each of which comprises 14 curved steel pieces that are each long. 
what does the holland tunnel look like underwater UNANSWERABLE what is this tunnel? It is a vehicular tunnel under the Hudson River is this tunnel built to connect cities? Yes, Lower Manhattan with Jersey City does the river flow through these aforementioned cities? Yes are there any other tunnels build under this river? Yes, Lincoln Tunnel who are the operating authority for the tunnel mentioned at the beginning? Port Authority of New York and New Jersey (PANYNJ) when was the aforementioned authority established? 1921
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Holland Tunnel [SEP] Tubes
The Holland Tunnel is operated by the Port Authority of New York and New Jersey. It consists of a pair of tubes with diameters, running roughly parallel to each other and apart underneath the Hudson River. The exteriors of each tube are composed of a series of cast iron rings, each of which comprises 14 curved steel pieces that are each long. The steel rings, in turn, are covered by a layer of concrete. Each tube provides a roadway with two lanes and of vertical clearance. The north tube is between portals, while the south tube is slightly shorter, at .