Mt. Wrangell - 14,000'
One of, if not the, largest active volcanic peak in North America. (to quote wikipedia) "The amount of geothermal heat being emitted by Wrangell has been increasing since the 1950s, raising the possibility of a future eruption" - which is a rather. . ."exciting" feeling.
It is quite a mountain to be sure.
[EDIT: also, for those of you who don't know, the cloud you see on the top is steam rising from the caldera]