The morphology of this island is complex and tormented and can be understood by a clever interpretation of the landscape. The first volcanic feature can be detected at a distance for the acrid sulfurous emanations from the pools of thermal mud. Immediately after, the Big Crater (also called "Fossa di Vulcano"), which is not very high (391m above sea level), offers a "strong" view, even if at first it seems to be in front of a sleeping volcano.