Today's photo of the day features the Strokkur geyser, a fountain geyser located in southwest Iceland. The eruption may look cool and refreshing, but that water is boiling hot - actually hotter even - and smells like rotten eggs. The geyser works a bit like a teapot: deep below ground, water becomes superheated (because it's in contact with rocks heated by magma) and pressurized (because it's so far beneath the surface). When enough pressure builds up, water and steam force their way upward through overlying rocks and explode at the surface (like a teapot whistle). Fun fact: the word "geyser" comes from the Icelandic word "geysir"!