The Kinzua Viaduct, located in Pennsylvania, was once the tallest and longest railroad viaduct in the world. Completed in 1882, it was designed to transport coal and timber across the Kinzua Creek valley. The structure is made of iron and spans 2,053 feet, standing 301 feet above the ground. In 2003, a tornado severely damaged the viaduct, leading to the collapse of several of its towers. Today, the site is part of the Kinzua Bridge State Park, where visitors can walk along a skywalk that offers stunning views of the remaining structure and the surrounding landscape.