In 1918, a road was needed from the village of Tolsta to the nearby fishing area at Garry Beach, on the Outer Hebrides of Isle of Lewis, Scotland, but after the bridge was built, by hand mixing the concrete, the terrain and the harsh weather made building a road impossible. Result? Bridge without a road to the destination

https://www.atlasobscura.com/places/garry-bridge-the-bridge-to-nowhere