On the high valley about 200 feet below the summit of Mt. Shasta, California lies a series of hot sulphur fumaroles that show that the peak is still active, though dormant.  The entire summit plateau smells of rotten eggs, the ground itself hisses w/ a warm sensation.  This is also the location of John Muir's famous survival during a blizzard on the summit of the peak in 1875.  While a few pools are visible, this panorama shows the overall area of geothermal activity.