Lummelunda Cave

Three schoolboys found the way in through a narrow passage in 1948, and the system explored since runs to something over four kilometres, cut by water through Gotland's Silurian limestone over a very long period. A stream runs through it and emerges at the entrance. About two hundred and fifty metres are set up for visitors with lighting and a path, showing stalactites, flowstone and the river channel; the rest requires caving equipment and permission. The temperature underground sits around eight degrees year round. Guided tours run through the summer season and the cave closes in winter, partly for the bats that hibernate in it.

What you actually see

• An underground river - running out at the cave mouth.
• About 250 metres set up for visitors - lit, with a path.
• Stalactites and flowstone - along the show section.
• A system over four kilometres long - most of it not open.

When to go

May to September, when tours run. An hour and a half.

Honest expectations

Only a small part of the cave is open. It closes for the winter and for bats. Eight degrees underground means a jacket in any season. Tours are timed and can sell out in July.

Nearby

Visby is south; the north-west coast runs on to Farosund.