Dale Creek Bridge, Union Pacific Railway

At a height of 150 feet, this bridge in Dale Creek, Wyoming, sometimes swayed in strong winds. The longest trestle on the Union Pacific Railroad's line, its soaring height and stilt-like supports still inspire awe. William Henry Jackson hiked partway into the dry, inhospitable creekbed to make this image, pointing his camera upward to maximize the bridge's height and to highlight the Union Pacific's engineering achievement.