The Sabatino volcano is one of two volcanic complexes in the central Italian region of Lazio, the other is located in Alban Hills. Around 600,000 years ago, the Sabatino volcano occupied the entire region from the coast to Mount Soracte. This led to the formation of various craters, such as the lakes of Bracciano and Vico. There are also other traces of volcanic activity. 

One such example is the otherworldly landscape of the Caldara di Manziana, a small caldera located northwest of Lake Bracciano near the town of Manziana and the eponymous forest.

Manziana's name is said to have derived from the Etruscan god of the underworld, Manth, and his presence was perceived by the Etruscans in geysers and volcanic springs across the region. 

Even today, a small geyser gurgles and bubbles at the center of a swamp fringed with what are most likely the only birch trees in the region. The geyser mostly emits CO2, with a small percentage of hydro-sulfuric acid and methane. Deposits of minerals and white-to-yellow colored clay create the perfect conditions for the formation of peatland at the site.