Yellowstone is proof of how violent Earth can be. Scientists estimate
that about 640,000 years ago, there was a gigantic volcanic
eruption in the area that is now the center of the park. The land
was destroyed as fast-moving lava flows covered the region, and at
the center, a huge crater called a caldera remained. Yellowstone's
volcanic activity continues today. Tourists flock to see the towering
waterfalls, gurgling hot springs, and gushing geysers.
However, Yellowstone is much more than hot springs and gushing
steam. It is also a beautiful place. The park sits on a broad, flat area
called a high plateau. It is surrounded by mountains and is drained
by several rivers. The park's boundaries enclose craggy peaks,
alpine lakes, deep canyons, and vast forests.
Morning Glory Pool is a colorful hot
spring. Its water is heated by melted
rocks that lie deep underground.
