28.4 miles:
33 minutes
SR 155 passes by one of the largest concrete structures in the world, the Grand Coulee Dam, which harnesses the power of the Columbia River as a source of energy and for flood control. Beyond the dam, giant natural cliffs and ancient geological formations lead into the silvery waters of Banks Lake.
![Map pin](https://www.aaa.com/AAA/common/drivetrips/images/maps/ID565082.png)