The Chesapeake Bay Bridge-Tunnel not only showcases the beauty of the Atlantic Ocean and Chesapeake Bay, but also the grace of an engineering marvel. Both a tourist attraction and a travel convenience, the Chesapeake Bay Bridge-Tunnel connects Virginias eastern shore with the Virginia mainland with a four-lane, 20-mile-long toll crossing of lower Chesapeake Bay. It carries U.S. Highway 13 with series of low-level trestles and high-level bridges interrupted by two approximately one-mile-long tunnels beneath Thimble Shoals and Chesapeake navigation channels. Manmade islands, each approximately 5 acres in size, are located at each end of the two tunnels. These islands were constructed with an astonishing 1.2 million tons of rock armor. It was statistics such as this that led the American Society of Civil Engineers to name the northbound portion of the project 1965 s Outstanding Engineering Achievement. It was also designated one of Seven Engineering Wonders of the Modern World.