We entered Yellowstone through the east entrance (out of five entrances), arriving from Cody. We gradually climbed to the altitude of 2500+ meters, so at some point there was quite a lot of snow. Yellowstone is a big plateau, elevated by the volcanic activity below it, but once you arrive in the park, there aren’t many mountainous peaks or deep valleys.
The park is enormous (bigger than some of the eastern states), and distances between various points of interest are quite big. It’s mostly a big forest with some geothermal features, waterfalls, plains filled with bisons and other goodies scattered around. We managed to come at a right moment - at the end of May, the season isn’t exactly started yet, so there wasn’t as many people as, say, in July, but the temperatures are already nice and the snow clears from the trails. After being welcomed by the frozen Yellowstone lake, we first stopped at West Thumb - a not-so-big area with hot springs and small geysers on the lakeshore.
On our way to the Upper Geyser Basin, where the famous Old Faithful is, we crossed the Continental Divide - the hydrological line that divides the areas from which waters drain either to the Atlantic or to the Pacific Ocean. Americans seem to really like their Continental Divide and they mark it wherever they can.
Old Faithful is located in the western part of the park, around 40km from the West Thumb and Yellowstone lake. The surrounding area is very developed - there’s a huge hotel (wooden, from early 20th century), visitor center, shops and restaurants. Old Faithful explodes each 90 minutes or so, so there’s always a crowd of people waiting for the spectacle. It isn’t very big though - the Geysir in Iceland is more impressive. The number of other geysers and hot springs in the neighbourhood is, however, unparalleled, and there are kilometers of paths that zigzag about them.
To see the Grand Prismatic Spring, the most interesting feature of the park, we had to drive 20 more kilometers through the dense forest. The parking of the Middle Geyser Basin fills up quickly even outside of the season - we had to wait in a queue to park. As opposed to the Upper Geyser Basin, there are just a couple of hot springs here, but they are all very big and colorful and overall great. A path from a bit farther away leads above the Eye and provides great views over the basin.
Driving further through the park, we encountered many smaller springs, geysers and also mugpods here and there.