Caldeira das Furnas is a volcanic crater located in the eastern part of São Miguel Island, one of the islands in the Azores archipelago of Portugal. The caldera is about 1.5 kilometers wide and is known for its bubbling mud pools, geysers, and hot springs.

The area around Caldeira das Furnas is an important part of the Azores' geothermal activity, and the hot springs and thermal waters are used for medicinal and therapeutic purposes. Visitors can observe the bubbling mud pools and hot springs and even see local chefs cook the famous cozido das Furnas, a traditional Portuguese stew, by burying it in the hot ground.

In addition to the geothermal activity, Caldeira das Furnas is surrounded by lush green vegetation, including the Terra Nostra Botanical Garden, which features a variety of exotic and endemic plants from the Azores and other parts of the world. The garden is home to a large thermal pool that is popular for swimming and relaxing.