A geo-thermal park located near Monterotondo Marittimo, is characterized by the presence of natural jets of steam and hot water from inside the Earth to the surface.
THE BIANCANE: The park's name comes from the colour of its characteristic rocks. The white colour is due to steam jets containing hydrogen sulfide, causing a chemical reaction that transforms limestone into plaster. Volcanism started in the Metalliferous Hills area 4 million years ago. The steam consists mainly of water vapor, spurting from the rocks at a temperature of 100 °. All the rocks in this area, due to the circulation of geothermal fluids, presentano variazioni nei colori e nella composizione.