Lagoa do Fogo is a lagoon that fills a big crater of a dormant volcano. This volcano forms the massive volcanic mountains of Serra de Agua de Pau, located in the center of São Miguel island. This whole area is surrounded by dense and exuberant endemic vegetation.
This volcanic crater, like the volcano that formed it, is the youngest on São Miguel island and will have been formed about 15 000 years ago. Its current configuration is the result of the last collapse, that took place on the top of the volcano, approximately 5000 years ago. The last eruption dates to 1563.
This lagoon is also the highest on São Miguel island, due to the fact that it’s at the top of a mountain, whose highest point is 949 meters long. It’s located at the top of the Vulcão do Fogo (fire volcano), also known as the Agua de Pau volcano. The crater has a collapsed and elliptical form, with approximately 3 x 2.5 km. The walls of the crater can be really uneven, reaching 300 meters.
Lagoa das Furnas is surrounded by abundant macaronesian vegetation and several volcanic phenomena such as the boiling hot springs and a sulfate smelling steam. The traditional Azorean stew, named ‘Cozido das Furnas’, is made on the margins of this lagoon, underground with the volcanic heat. Also, in the margins of this lagoon is one of the most curious chapels on São Miguel island, dedicated to Nossa Senhora das Vitórias, that was intended to be the mausoleum of José do Canto and was solemnly inaugurated in 15 of August of 1886.
Lagoa das Sete Cidades was formed by successive collapses of two reliefs that surround it. This lagoon has a diameter of about 5 km and the walls reach a maximum altitude of 400 meters. It is one of the largest collapsed craters in the archipelago. Its walls have, for the most part, very steep sidehills. Pico das Éguas is the highest point, with an altitude of 873 meters. The surroundings of the lagoon include an urban area, farm lands and forests filled with cryptomeria. Lagoa das Sete Cidades is the largest natural freshwater reservoir in the Azores, occupying a vast area of 4.35 square kilometers, with a depth of 33 meters.