This is the plume you saw in the background of yesterday's photo. This crater is near the Volcanoes National Park. Sometimes this area is closed, depending on the way the wind blows. Although it looks like steam - this is actually a plume of gases which can be poisonous if inhaled in large quantities. It was a very cool day - we even saw some molten lava flowing (from a great distance) as we cruised by the island that night.