This island with its smoking volcanic pools and bubbling sludge resembles a relic from some distant past. The impressive crater rises 386 meters, and can be easily and safely viewed from the top where you can see the two harbours to the east and west. You can also look down to the Valley of the Monsters (Valle dei Mostri) and see the silhouettes of the surrounding islands. The island is definitely worth a visit for nothing else but to see the alum caves and the sulphur mines where during Bourbon times an army of prisoners was forced to mine.
On the northwest side of the island lies the Grotta del Cavallo (the horse grotto) on a wild and deserted stretch of the coast, which gradually slopes down to the black Gelso Beach. Here you will find clusters of Euphorbia and sprawling cacti growing down over the cliffs.
