This was in an area called Midway Geyser Basin which is north of Old Faithful. There were several deep pools that were bubbling and steaming.
In the same area was a huge hot spring called Grand Prismatic Spring. This picture barely does it justice. The red/orange at the bottom of the picture is a wide bacteria flat that surrounded the spring. The center of the spring was vivid turquoise that was often obscured by the steam it was emitting.
We caught the 2:10 showing of Old Faithful. Pretty amazing that after all these years it still erupts every 90 minutes.
Throughout the day we saw several herds of Elk and Bison. More often than not, the animals were right at the side of the road. They seemed to enjoy creating traffic diversions for the humans. Here are a couple of pictures of them:
One particularly spectacular area is called West Thumb. It's a thermal area on the shore of Yellowstone Lake. Here is Lakeshore Geyser:
The lore of Fishing Cone Geyser was that you could catch a trout in the lake and while it was still on your line, you could cook it in the boiling water of the Fishing Cone. Fishing is not allowed these days…
This smaller geyser was in an area of West Thumb called the Fumaroles. We were attracted to it because it was particularly active, and had a bright green rim. The colors in all of the springs and geysers are created in part by the micro-organisms that live in them.
As the sun was setting we made our way to the Grand Canyon of Yellowstone. Here's a picture of the Lower Falls of the Yellowstone River.
It was a long day in the park. We are both amazed by the size and splendor of Yellowstone. It is truly remarkable to see so many different wonders of nature in such a relatively small area.