A road trip from Las Vegas to Yellowstone and back again in July 2010

"Yellowstone is a national park located primarily in the U.S. state of Wyoming, though it also extends into Montana and Idaho.
Yellowstone was the first national park in the world (1872), and is known for its wildlife and its many geothermal features, especially Old Faithful Geyser, one of the most popular features in the park.

Yellowstone National Park spans an area of 3,468 square miles (8,980 km2), comprising lakes, canyons, rivers and mountain ranges. Yellowstone Lake is one of the largest high-altitude lakes in North America and is centred over the Yellowstone Caldera, the largest supervolcano on the continent. The caldera is considered an active volcano; it has erupted with tremendous force several times in the last two million years. Half of the world's geothermal features are in Yellowstone, fuelled by this ongoing volcanism. Lava flows and rocks from volcanic eruptions cover most of the land area of Yellowstone. The park is the centerpiece of the Greater Yellowstone Ecosystem, the largest remaining, nearly intact ecosystem in the Earth's northern temperate zone.

Hundreds of species of mammals, birds, fish and reptiles have been documented, including several that are either endangered or threatened. The vast forests and grasslands also include unique species of plants. Grizzly Bears, wolves, and free-ranging herds of bison and elk live in the park. Forest fires occur in the park each year; in the large forest fires of 1988, nearly one third of the park burned.:
Wikipedia

Yellowstone National Park