The Mackinac bridge

At the time of construction in 1957, the Mackinac bridge, at five miles, was the longest suspension bridge ever constructed, with its main span of 3,800 feet. It was a engineering challenge to build the caissons that would support the bridge.

All the details are covered in the book, Miracle Bridge at Mackinac by David B. Steinman and John T. Nevill ( 624 ST). David Steinman is a bridge engineer and John Nevill was a newsman.

In upper Michigan, before the bridge was built, people had to ferry from Mackinaw City to St. Ignace to reach the upper peninsula of Michigan.

In some books that I've read, the authors can get bogged down with too much technical information. These authors do a fairly good job of trying to explain some of the challenges of building the bridge so that the common person can understand it. Interestingly enough, they use the analogy of a can of vegetables to explain building the supports that are underwater.

According to the U.S. Department of Transportation, the record holder now is the Akashi Kaikyo Bridge in Japan with a main span of 6,5332 feet (compared to Miracle Bridge's 3,800 feet). See the following website for more information on the Akashi Kaikyo Bridge:

http://www.tfhrc.gov/pubrds/julaug98/worlds.htm

c Waterloo Public Library 2007