Not too far outside (and above) La Paz, Bolivia, is Chacaltaya, once upon a time the highest-elevation ski resort in the world. The glacier melted and the snows no longer fall, so it’s no longer operational. But it makes for a great day trip. A tiny bus took a small group of us (on what in some places is a VERY hazardous road) right to the old lodge, and from there we hiked the last couple of hundred feet to the nearby summit. It’s all above 17,000′ (the peak is at 17,178′), so the walk was slow and, quite literally, breath-taking. As in “it was very difficult to breathe”. Well worth doing, but give yourself a couple of days in La Paz first to somewhat acclimate before tackling this altitude!