The Furna de Frei Matias is arguably the most renowned volcanic cavity on Pico Island, referenced to have served as a shelter for a hermit. This geosite comprises the four sections that make up the “Cave System of Furna do Frei Matias,” currently not interconnected and collectively spanning a mapped total extension of about 920 meters. With maximum width and height of 14 meters and 7 meters, respectively, these sections feature several skylights, often allowing access to the lava cave. This is one of the most fascinating volcanic cavities in the Azores, distinguished not only due to the diverse geological structures present (such as lava stalactites and stalagmites, ledges, gas bubbles, striated walls, and pahoehoe and aa lavas) but also for hosting various endemic species of cave fauna and mosses vicinity of the main entrance. It’s worth noting that the basaltic lava flow that gave rise to this cave system was emitted from the spatter cone of Alto do Morais, where a volcanic shaft with a depth of 65 meters developed. This geosite holds regional significance and serves scientific and geotourism purposes.
