The volcanic caldera, also known as Caldera Furnas, is one of the most visited places in the entire Azores archipelago. The various phenomena of active volcanoes at the site contribute to this attraction. Other attractions include sulfur sludge and the huge amount of water sources scattered in the area; Some are hot and others are mild or even cold or gaseous, and surprisingly, this water emanates from deep within the earth in the form of gas.