Yellowstone was pretty wild. We seriously felt like we were on another planet. Geothermal activity is pretty sweet. We saw a few bison, one was only 25-30 feet from us! I was so excited. There weren't a lot of people there since it was the off season. The science behind it all was really interesting. The park does a really good job with informative yet innocuous signage. Wowie...words can't really describe it well, so here are some pictures.
Old Faithful!
AHHH! Those little pools are filled with boiling water.