What U.S. volcano do more than 2 million people visit each summer?
(Hint: It had an explosion 1,000 times larger than Mt. St. Helens' explosion.)
For a huge clue, see this century's last commemorative coin—the Yellowstone National Park Commemorative Silver Dollar.
Yellowstone National Park?
That's right—the park sits on top of a volcano that erupted 600,000 years ago.
Today, the Yellowstone Hotspot produces the park's 10,000 geysers, hot springs, steam vents, and mud pots.
You can find more of these "thermal features" in the park than in the rest of the world combined.
In fact, 75 percent of the world's geysers are in Yellowstone!
The front (obverse) of the Yellowstone National Park Commemorative Silver Dollar shows one of these geysers erupting steam.
The coin's back (reverse) has an American Buffalo.
Both geysers and bison can be seen throughout the park's 2.2 million acres.
What else makes Yellowstone such a hot tourist spot?
It's the world's first and oldest national park!
Yellowstone was "dedicated and set apart as a public park" by an act of Congress on March 1, 1872.
This act, signed by Ulysses S. Grant, was the start of our National Park Service.
Obverse: The coin's obverse shows an erupting steam geyser. Three out of every four geysers in the world are found in Yellowstone National Park!
Reverse: An American Buffalo, Yellowstone's largest mammal, appears on the coin's reverse.