Iceland

It fits into four days and holds nearly everything strange about Iceland. You leave the hot springs of Landmannalaugar through rhyolite mountains that look painted by hand, cross a plateau of snow and obsidian at the highest point, then descend through black-sand deserts to a birch forest at Þórsmörk. What asks for your attention isn't the climbing — the trail is well marked — it's the rivers: three you cross on foot, their levels shifting within the same day as it rains or the sun comes out. Come in July or August, book the huts early, and read the wardens' conditions board before every ford.