Travel the World: Yellowstone

Native Americans lived and hunted in the Yellowstone area for at least 11,000 years before the land was set aside for the public trust.

In 1872, the United States' 42nd Congress declared Yellowstone a national park and President Ulysses S. Grant signed the act into law.

According to the National Park Service, when Yellowstone's supervolcano exploded in the park for the first time it spewed roughly 2,400 times the amount of mass that Mount St. Helens managed in 1980. The last time there was actual lava flow in the park was around 70,000 years ago, and the last caldera-forming eruption occurred about 640,000 years ago. All in all, as the Yellowstone region has gradually passed over this volcanic hotspot, it has been the scene of three caldera-forming explosions, which taken together ejected enough lava and ash to top off the Grand Canyon.

Although sources vary on the exact size of the caldera basin, most put its dimensions somewhere around 30 by 50 miles in size.

According to the National Park Service, Yellowstone sports about half of the planet's hydrothermal features, including more than two-thirds of its geysers. Hot springs, mudpots and fumaroles make up the rest -- numbering more than 10,000 when all's told.

Fumaroles are a lot like hot springs, only they're so hot the water boils away before it can reach the surface so only steam and gases pour out. The Black Growler Steam Vent is the hottest fumarole in the park -- it ranges between 199 degrees and 280 degrees Fahrenheit (93 and 138 degrees Celsius).

Bison have lived continuously in the Yellowstone area since prehistoric times. Visitors to the park will often see Yellowstone's herds calmly milling around with little regard for the spectators gawking from their cars. But don't be fooled; despite being around 1,000 to 2,000 pounds when fully grown, bison can run up to 30 miles an hour and turn on a dime. (That's about 450 to 900 kilograms and 50 kilometers an hour.) So it's important to give these big beasties some space!

Geysers come and go, and some have surpassed Steamboat Geyser in the past, but it currently takes the cake for tallest active geyser in the park -- and the world, in fact. When the geyser has a major eruption, it can shoot water more than 300 feet (91 meters) into the air. Major eruptions are highly variable however. Since 1878, 166 have been recorded with the intervals between ranging all the way from 4 days to 50 years.

The Mammoth Hot Springs' terraces are formed out of travertine, which is bright white when first deposited and weathers into gray. The striking colors of the terraces come from the bacteria, algae and other microorganisms that find the environment copasetic.

From the first couple hundred people who came to the park the year it was founded, the number of visitors has grown to about 3 million a year in recent years.