Sangumburi Crater

This guide to Sangumburi Crater on Jeju opens with the single violent blast that carved it around seventy-three thousand years ago, leaving a rimless hollow unlike the island's more than three hundred sixty other volcanic oreum. It follows geologists who still argue over what to call the crater's odd downward shape, and how its sheltered bowl grew into its own microclimate. Listen for how the vegetation splits by exposure, cool-climate trees clinging to one shaded wall while warmer species crowd the sunlit side.