Yellowstone is truly a unique place.  Oh, there is plenty of wildlife to see and the landscapes are striking.  What really stands out are the live volcanic features.

I always tried to leave the camp early.  Early enough to avoid the tourists. This allowed me to view these features in solitude.  Many times I felt as if I had traveled back in time and was watching the beginnings of our planet.

A primordial ooze appears to be flowing to the surface everywhere you look.