Half Dome day hike
First of all, I'll make it known that I did NOT do this hike. But I'll going to journal this to brag on my girlfriend, because she did do it last week. I'm not certain I could even do it. I think it may be just beyond my abilities at this point.
So, Half Dome in Yosemite National Park. Universally accepted as one of the most difficult day hikes in the country. Only 300 hikers allowed per day, and those must have permits that are given out in lottery-style drawings. She went with her daughter, the daughter's boyfriend, and another friend. Those others from her hiking party are all 25+ years younger than my girlfriend, and all are in great shape since they all run or lift or workout regularly.
They left their accommodations to start the hike at 4am, and didn't get back until 8pm. On this hike they recorded 50,000+ steps, did almost 5000 feet of elevation gain, and did it across some really difficult surfaces, including bare rock at a steep angle. The pics she brought back were amazing. Seems to me to be an incredible feat.