What's the highest terrestrial elevation that you've ever climbed, hiked, or otherwise been to?

If the highest point on Earth that you’ve ever hiked or climbed to is lower than the highest that you’ve ever been to, then I’d like to know the elevation of that point too.

E.g., if you’ve hiked up to the summit of Mt. Whitney (14,495 feet) and driven up to the summit of the world’s highest road (about 18,000 feet as I recall), then I’d also like to read about your hike or climb up to the top of Whitney.