The rim-to-rim is a 24 mile one-way hike through the Grand Canyon. The most typical route is to start on the north side and exit on the south side (full route). It took us about 12.5 hours total including breaks + a detour to Ribbon Falls (making the total mileage about 25 miles). This wasn't technically backpacking, since we didn't spend the night on the trail. But, it felt epic enough to make the list!
Headed out around 3pm. The descent from the north rim was easy and smooth. Sunny, perfect temps, nice breeze. About 8 miles in, I took a detour to check out Ribbon Falls - a magical/mossy waterfall. Right after the detour, the sun started setting. Felt wrong to still be on the trail after dark. My animal instincts were saying, what are you doing out? Get inside! That feeling faded after about 20 mins. The bottom of the canyon was surprisingly warm even after dark.
After sunset, Joe and I ran into a hiker that seemed a little panicked. Turned out she was hiking rim to rim and BACK AGAIN! But, she was in over her head and exhausted. Joe invited her to hike with us, which she took us up on. She ended up hiking with us for hours.
We kept our headlamps off as it got darker. At this point, the moonlight couldn't get to where we were so it was hard to see. But, a fun eyesight challenge. As we came upon Phantom Ranch (about 15 miles in), we finally got the full moon's light. It was so bright, felt like the sun was out.
Took a brief stop at Phantom Ranch to eat a little and tape up some blisters. Then started heading up Bright Angel. After a few miles of ascending, our companion waved us on to go ahead of her. We were relieved because she was going way too slow at this point and it was stressful feeling responsible for her. There were enough other groups (saw maybe ~8 total?) doing rim-to-rim, so we didn't feel guilty leaving her behind.
As it got later, the hiking started feeling really trippy. The light from the moon is cool, so everything looked grayscale and slightly tinted blue. That combined with the canyon's landscape made it feel like we were on the moon or some alien planet.
We finished the hike at around 3am, after ~12.5 hours on trail.