The history of road construction in Yellowstone Park is an interesting read. From this overview point looking eastward down the canyon, you see the remnants of the once main passageway from the East Entrance to Fishing Bridge, as well as the Corkscrew Bridge. The steep slope of the canyon required the spiral bridge configuration to allow wagons and horse-drawn carriages, and later vehicles, to better navigate the terrain.
 

The first wooden corkscrew bridge was built in 1904. A few variations to the bridge were implemented in 1916. Then, in 1919, the National Park Service built a new concrete Corkscrew Bridge in the same place as the original wooden structure. On the west face of the bridge, there is an inset that reads “N.P.S. 1919”. By 1929, a new and improved road was cut into the north hillside bypassing the bridge.

 

A hike down to old Corkscrew Bridge along the southern side of the canyon allows you to see some remnants of the roadway, including metal and log framework and stone retaining walls, etc. You will also see items left by travelers such as old rusty tin cans, stone ring fire pits, broken plates, etc. From a view atop the old bridge, you can see how the old road snaked up and down the canyon.