Photo source: www.highestbridges.com

4. Aizhai Suspension Bridge, China – This bridge connects two tunnels in China. It took 5 years to build costing $600 million. It is known as the world’s longest suspension bridge. Opened in 2012, the bridge sits 1,200 feet over the Dehang Canyon and spans a tower-to-tower distance of 3,858 feet. The mountains on either side anchor the suspension towers.