Fifty years ago this summer, the Mackinac Bridge started to take shape when construction shifted from subsurface pier construction to that of the superstructure, thus presenting a more visible outline of the modern day wonder that soon would link Michigan’s Upper and Lower Peninsulas. The bridge eventually would eliminate the need for travelers to wait for hours to make the trip on car ferries. On July 2, 1955, American Bridge Company of Pennsylvania took over surface construction on the two 552-foot towers of the Mackinac Bridge. Sections of the steel towers were fabricated in Ambridge, Pennsylvania, and Gary, Indiana. They were shipped to St. Ignace, where they were placed on barges and floated out to their final location be erected in the Straits of Mackinac. Bob Sweeney, secretary of the Mackinac Bridge Authority, explained that sections of the towers were temporarily held in place by bolts until 220,000 rivets could permanently lock tower sections together. (Photographs courtesy of Mackinac Bridge Authority)