Fumaroles
Fumaroles are openings in the Earth's crust, typically found near volcanoes, through which steam and gases are emitted. These gases are often hot and can contain various minerals and chemicals. Fumaroles are a type of hydrothermal vent and are formed when water seeps down through the ground and is heated by magma, causing it to rise back to the surface as steam. These geological features are known for their distinctive sulfuric smell and can be hazardous due to the high temperatures and toxic gases they emit.