Moki Dugway on State Route 261 in San Juan County, Utah. The highway descends/climbs 1,100 feet in just 3 miles on a dirt road carved out of steep rock cliffs.
<a href="//commons.wikimedia.org/wiki/User:Dschwen" title="User:Dschwen">Daniel Schwen</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>