Geomunoreum

Geomunoreum is the source. Around three hundred thousand years ago it erupted and the lava that poured north-east from it hollowed out as it drained, leaving the Geomunoreum lava tube system - Manjanggul, Bengdwigul, Gimnyeonggul, Yongcheondonggul and others, among the finest lava caves anywhere and the reason Jeju's volcanic landscape was inscribed by UNESCO in 2007. The cone itself is forested, with a deep horseshoe crater, and the walk is a guided loop of a few kilometres taking two to three hours through dense evergreen and deciduous woodland, past charcoal kiln sites and old dug tunnels, with the crater and the tube system explained on the way. Access is deliberately restricted to protect it: numbers are capped, visits must be booked in advance, guides lead every group, it closes on Tuesdays, and turning up without a reservation does not work.

What's there

• The horseshoe crater - the forested cone at the centre.
• The tube-system explanation - where the lava ran and what it left.
• The forest walk - the guided loop through dense woodland.
• The old kiln sites - charcoal workings and tunnels in the wood.

When to go

April to June and September to November. Book well ahead - daily numbers are capped, and it closes on Tuesdays.

What to expect

No reservation, no entry - this is enforced. Visits are guided and follow a fixed route at a set pace, largely in Korean. The lava tubes themselves are separate sites, and most are closed to visitors entirely.

Nearby

Manjanggul lava tube is open to visitors nearby; Bijarim and Sangumburi are close.

Key facts