Grand Canyon has my heart forever. The sheer magnitude of the canyons and the history of the earth it contains brings breathtaking awe to those who are lucky enough to visit.
This trail is 16 miles long (when I measured it, it ended up being 18 miles on Strava!) with an elevation profile of 5000+ft. It took me a total of 9 hours, with 7+ hours of moving time. I'd do it again in a heartbeat.