Cueva de la Vaca

This is not a show cave with walkways. The route runs about a kilometre and a half into the limestone with an underground stream through it, and the water is waist to chest deep for much of the way and deeper in places - you wade and in some sections swim, in the dark, with helmet lamps, for something over an hour each way. Formations are extensive and there are chambers where the guides turn the lights off. Near the far end there is a narrow squeeze that has to be passed on your side, which is where people who are going to turn back usually do. Guides are mandatory and go with every group. Bats live in the cave. Rain upstream raises the water level and trips are cancelled for it.

The landscape

• Chest-deep water in the dark - waded and swum for over an hour.
• A narrow squeeze near the end - passed on your side.
• Extensive formations - with lights-out sections.
• A resident bat population - through the chambers.

When to go

December to March; trips cancel after heavy rain. Half a day.

Before you go

This is genuinely not for the claustrophobic or weak swimmers - the squeeze and the deep water end trips for people every week. Water levels close it after rain. You will be soaked and cold. Guides are compulsory for good reason.

Nearby

Cueva del Indio is close; San Gil is south.