The Owakudani Trail

90-minute walk through one of Hakone's most geologically active areas, where sulfurous steam rises constantly from vents that have turned lava into soft white clay. Starting near the Visitor Center, the trail passes Funami Iwa, a giant rock swept to its current position by a volcanic debris flow around 3,000 years ago. Higher up, the forest transitions from cypress and beech to increasingly sparse vegetation, with most trees near the valley floor having died following a 2015 eruption that raised sulfur dioxide levels. The trail ends beside the Hakone Geo Museum and a shop selling the famous black eggs, hard-boiled in sulfurous water.