sum of all geysers in the world do not exceed the total of Yellowstone.
hot spring at Yellowstone National Park
Yellowstone has the largest concentration of geysers in the world in the Upper Geyser Basin. Grand Geyser, which is pictured in the photograph, is just one of the many geothermal features in the area. It is the largest predictable geyser in the world, with eruptions occurring every 7-15 hours and lasting 9-12 minutes. An eruption typically consists of 1-4 bursts which may reach over 200 feet.

Chris and I were very fortunate to be in the Upper Geyser Basin while Grand Geyser was erupting. Although the geothermal feature is claimed to be predictable, there is still an 8 hour eruption time uncertainty. Watching this geyser spew water over 200 feet certainly gave us a greater appreciation for the power of these geothermal features.
Yellowstone N.P. is renowned not only for its geothermal features but for its wildlife as well. Currently, the park is home to about 4,000 buffalo. From our visit, Chris and I learned several interesting facts about the buffalo. First of all, buffalo and bison are synonymous terms. Indians had originally called these animals bison. However, when early Europeans settled the land, they named the creatures buffalo; supposedly the bison reminded the settlers of water buffalo from home. :) Another interesting fact is that buffalo have been known to gore visitors that approach them too closely. So if you ever visit Yellowstone, heed the ranger warnings and keep a safe distance from the wildlife.
Another major geothermal feature of Yellowstone is the Mammoth Hot Spring Terraces. Effectively, a Mammoth terrace is a hot spring which is situated in an area with a large limestone foundation. It is believed that the limestone was deposited millions of years ago by vast numbers of sea animals; most sea creatures have shells which consist primarily of calcium, one of the main elements in limestone. As hot water in the hot spring terrace is forced towards the surface, it dissolves the limestone into solution. The limestone is forced out of solution and deposited upon the land as traventine when the water reaches the surface and begins the cool. Although traventine is white rock, oranges, greens, and browns are apparent in the picture. These colors are masses of living bacteria and algae that thrive in the extremely high temperatures of the terraces.

(Lisa's personal note) From the photo, it is probably easy to understand how I could be completely overwhelmed by the beauty of these hot spring terraces. Of all the areas visited on the trip, the Mammoth Hot Spring Terraces were my favorite!
Yellowstone's Canyon is not a highly advertised feature of the park, but it is certainly very beautiful and definitely worth a visit. The Canyon, which is 20 miles long and 800-1200 feet deep, has two falls known as the Upper Falls and Lower Falls. This is the Lower Falls on a beautiful sunny day. Mist from the water plummeting 308 feet downward creates the two beautiful rainbows. Under the rainbows are small creeks formed by the mist hitting the canyon wall.

To reach the Lower Falls, we had to walk down a flight of over 300 stairs. The trip back to the car was grueling, but the pictures we captured made the effort worth every bit of sweat.