Steam from a hot springs.
Hot springs are pools created and heated by geothermal activity. While many of these springs are too hot for humans to enjoy, some hot springs exist where people can soak and enjoy the warm water.
Many hot springs are heated by nearby volcanoes, warmed as the water comes into contact with magma. While many of these pools reach over 110 degrees Fahrenheit, people have learned control temperatures, so they are safe for people to enjoy.
Hot springs are found throughout the world, especially in places with volcanic activity like Japan, Iceland and parts of western United States. Other famous hot springs in the United States include Glenwood Springs in Colorado and Hot Springs in Arkansas.
If you are familiar with hot springs, you will know they have a distinct aroma that smells almost like rotten eggs. That smell comes from a gas called H2S (hydrogen sulphide). It can be unpleasant, but it’s a small price to pay for soaking in warm water.