Unzen Jigoku (Unzen Hell) — Active Volcanic Vents

**Onsen tamago (hot spring eggs):** Vendors at the trail entrance sell eggs boiled in the 90°C volcanic steam — the whites turn partially opaque but the yolk stays soft. ¥100 for 5 eggs, eaten on-site with salt. **Night visit:** The steam plumes are illuminated after dark (18:00–22:00), creating an eerie effect — the clouds of vapor glow against the black forest. Almost no tourists visit after 19:00; the experience becomes genuinely uncanny. **Mt. Unzen hiking:** A trail from Jigoku leads to Mt. Fugen summit (1359m, 3 hours round trip). The 1990-95 eruptions created a new lava dome visible from the summit — one of the youngest geological features in Japan.