Beside the river at Pe de Passo are the Sao Vicente Caves, a series of lava tubes left after an eruption that occurred about 400,000 years ago. These volcanic tunnels extend for about 3,281ft (1,000m) and can be explored on a 30-minute tour. The caves feature formations like lava cakes, volcanic stalactites and erratic blocks and give a sense of walking through the bowels of the earth.

Website: www.grutasecentrodovulcanismo.com

Telephone: 291 842 404

Opening times: Daily 10am - 7pm

Admission: €8 (adults), concessions €6