Mauna Loa Summit Trail

This is not a casual day hike — it's a pilgrimage across the roof of the world's largest volcano. Starting from the Mauna Loa Observatory at around 11,000 feet, you'll cross miles of barren, wind-scoured lava fields where the only company is the crunch of cinder beneath your boots. The trail is rough and unmarked in places, following ahu (stone cairns) across flows that range from smooth pahoehoe to ankle-twisting a'a. The air is thin up here, and every step above 12,000 feet reminds you of it. The payoff is Mokuaweoweo, the massive summit caldera — a moonscape so vast it swallows sound. On clear days, you can see Maui floating on the horizon. This trail belongs to summit baggers and volcano obsessives who want to earn one of the most remote high points in the Pacific.