The heavy lifting portion of the 91-year-old Wells Street Bridge in Chicago has begun. Construction crews first arrived on the scene back in November 2012, but removal of the leaf sections of the double-decked bascule span began on March 1. It marked the first of two nine-day windows where work will be done to reconstruct the historic structure. As the old leaves are removed, new ones are barged up the Chicago River and put into place.