The Grand Canyon rim-to-rim-to-rim (R2R2R) double-crossing is an amazing 46-48 mile journey, depending on your route, with over 11,000′ of elevation gain in temperatures varying well over 70 °F (21 °C).
The run is typically done from the South Rim to the North Rim and back, often starting on South Kaibab trail down to the river and Phantom Ranch since it’s steeper but shorter, along North Kaibab trail to the North Rim and back, but then back up to the South Rim along Bright Angel trail which is a little more runnable and with frequent water stations.
It’s on many an ultra runner’s bucket list, and for good reason. The incredible views and beauty this route offers at every turn are hard to beat.