Caldeira Velha

Caldeira Velha is a 13-hectare natural monument located on the north slope of Serra de Água de Pau, near Lagoa do Fogo. The area features a fumarolic field and a thermal spring with temperatures around 32°C, as well as thermal pools with temperatures of 38°C. The vegetation is dominated by non-native species, but some native Azorean flora can be found, including Erica azorica, Hypericum foliosum, and Ilex azorica. The area is also home to various bird species, such as the milhafre, tentilhão, and estrelinha, as well as the rã-verde in the stream. A visitor center provides information about the natural heritage of the Azores and the thermal and geothermal phenomena of São Miguel Island