Construction on the Second Avenue Subway's 72nd Street Station cavern as of March 7, 2012. Workers use these tags to check into and out of the work site. Photo by Metropolitan Transportation Authority... more 
Construction on the Second Avenue Subway's 72nd Street Station cavern as of March 7, 2012. Workers use these tags to check into and out of the work site. Photo by Metropolitan Transportation Authority / Patrick Cashin. less 
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Yahoo News | Photo By Metropolitan Transportation Authority / Patrick Cashin
Thu, Jun 13, 2013 5:00 PM EDT