Each autumn, meltwater carves new caves beneath Europe's largest glacier, and from November to March guides lead small groups inside — cathedral spaces of rippled, glassy ice glowing an implausible sapphire blue. Every cave is different every year, which is half the romance. Tours run from the Jökulsárlón glacier lagoon in super-jeeps; crampons and helmets are provided and the walking is short and manageable. Book a morning slot for the best light, and pair it with iceberg-spotting on the lagoon.
Featured in Ten winter adventures beyond the ski piste · Adventure