What Is the Largest Construction Project of All Time?

No, it's not the pyramids, or the Great Wall of China, or any of the giant skyscrapers of modern times.

The largest single construction project in all history is the United States Interstate Highway System, a network of super highways that crisscrosses America. When it is completed, during the 1980s, the project will include more than 42,000 miles of highways!

Three of the Interstate Highways stretch from the Atlantic Ocean to the Pacific, the longest covering over 3,000 miles. Another highway stretches over 1,860 miles from Maine to Florida.

And Interstate 75 runs 1,564 miles, from the Canadian border at Sault Ste. Marie, Michigan, all the way to Tampa, Florida, without a single traffic light!