THE MIGHTY MAC As you approach the Straits of Mackinac, seeing the rising towers of the Mackinac Bridge elicits a deep awe. This five-mile work of genius connecting the Upper and Lower Peninsulas of Michigan opened to car traffic on Nov. 1, 1957. Sixty years later it is still the longest suspension bridge in the western hemisphere. Cross it. Let it free your spirit. D r . D. S teinman -i ngeniouS a rchitect Dr. David Steinman, a New York engineer, designed the “Mighty Mac.” The bridge is built to withstand winds up to 600 mph, constant changes in traffic weight and the Straits’ extreme temperature fluctuations.