Aerial view of Upper Geyser Basin. Photo by NPS Jim Peaco

Yellowstone is the largest active geyser field in the world. Home to 60 percent of the world's geysers, Yellowstone delivers big when it comes to providing visitors with views of these strange, mysterious, odd-smelling steaming vents and spouting features.

The Upper Geyser Basin is Yellowstone's largest geyser basin and is home to the world's largest single concentration of hot springs. The whole geyser basin occupies only one square mile.

Located between the Old Faithful area and the Biscuit Basin road, the Upper Geyser Basin contains several groups of hot springs, including over 150 geysers. The basin is less than a half-mile wide and most of its geothermal features are situated within a few hundred feet of the Firehole River.

For visitors to fully appreciate Yellowstone, they must experience the park's geothermal wonders. Explore the geyser basins by taking a stroll down a boardwalk, or spend a full day watching a particular area's geysers erupt or hot springs gurgle. Take in their unique odors and odd sounds.

According to Katy Duffy, West District Interpretive Ranger in Yellowstone, the Upper Geyser Basin provides visitors with a "window" to beneath the earth.

"There are more active geysers in this basin than anywhere in the world," she says. "It's the reason Yellowstone was set aside as a national park and this area reminds you of that incredible idea. It's wonderful to watch the show at Upper Geyser Basin. Each of geysers plays differently."

It is recommended that those planning a visit to the Upper Geyser Basin spend at least two to three days to discover and appreciate the personality of this unique and large concentration of geothermal wonders.

But, more than likely, you only have a few days, total, to see the park. If that's the case, spend a few hours exploring the Upper Geyser Basin.

To make the most of your time, start with a stop at the Old Faithful Visitor Center, where friendly rangers can tell you when to expect certain features to erupt.

Following is a brief overview of some of the most popular geysers in the Upper Geyser Basin.

Yellowstone's Old Faithful Geyser Jeff Vanuga

Old Faithful Geyser

Old Faithful is the most famous geyser in America, and some people even call it the most famous in the world. It was discovered in 1870 by the Washburn Expedition, whose members stumbled upon the geyser during eruption. Can you imagine seeing Old Faithful for the first time? Today, seeing the geyser erupt for your first time must be almost as impressive. Due to the geyser's frequent eruptions, Washburn Expedition members named it "Old Faithful." The name was a good one. In fact, Old Faithful geyser has erupted more than a million times since Yellowstone became the world's first national park in 1872.

On average, Old Faithful erupts about every 65-95 minutes. Old Faithful shoots a column of water 100-130 feet into the air.

The length of the geyser's eruption determines how long it will be before the next eruption occurs. Therefore, longer geyser eruptions mean waiting longer to see the next eruption.

"If the eruption lasts more than two-and-a-half minutes, the wait time between will be about 94 minutes," says Duffy. "If it's a shorter eruption, wait time is reduced to about 65 minutes."

Old Faithful, like most of the park's geysers, gets its water from the depths of the earth. Snow and rain water reach depths of about 10,000 feet below the earth, at which point it's heated by the magma body, which forces it up through the surface.

Shortly before Old Faithful's show, water splashes and pressure builds.

Beehive Geyser

Beehive gets its name due to the appearance of its four-foot-high cone, which is shaped like an old straw beehive. But others contend that the geyser gets its name from having an eruption that sounds similar to an "angry swarm of bees."

It is the classic cone geyser. Beehive's vent is narrow - just eight inches in diameter - and acts like a nozzle so that a slender column of water is shot under great pressure. Average eruptions are around 150 feet high, but the geyser has been known to shoot water as high as 200 feet.

Beehive is one of the more forceful, powerful geysers in the basin. Water shoots through an eight-inch opening, and as a result, eruptions are very loud. It's a really spectacular geyser to see erupt.

Sawmill Geyser

Sawmill Geyser is situated and connected to about 10 other geothermal features that all compete for energy and water. Each geothermal feature pulls and draws energy and water from one another.

One geyser starts pulling water, so the others in the group have to wait until that particular active geyser is done and has a chance to fill up again. Eventually, the whole system fills as one.

Sawmill is a fountain geyser and erupts in bursts and surges. It erupts frequently. In fact, it's more common to see it in eruption than not in eruption

Giant Geyser

Giant erupts very infrequently.

Although this geyser is not one you'll want to wait around for, its shows are awesome. Living up to its name, Giant shoots water up to 300 feet into the air for about an hour at a time. During eruption, it discharges about one million gallons of water.

Castle Geyser in the Upper Geyser Basin. Photo by Jeff Vanuga Jeff Vanuga

Castle Geyser

Castle is most interesting because of its stored energy. Because it accumulates so much energy, after just 15 minutes or so, it has already eliminated most of its water and goes into a raucous steam phase that roars like a train.

Castle erupts from one of the largest cones in the Upper Geyser Basin. Its cone is 30 feet tall. Castle erupts about approximately every 12 hours. Eruptions usually last about 50 minutes. The first 20 minutes is a water eruption, followed by a 30-minute steam phase. Expect water to shoot about 70 to 80 feet into the air.

Riverside Geyser

This geyser is worth seeing because it's so unique. It erupts over a river.

Riverside shoots water at a 60-degree angle across the Firehole River every six hours or so. The water shoots about 80 feet across the river's water. Check this geyser out in the afternoon and you may even see a rainbow amidst the eruption. This geyser erupts for about 20 minutes at a time.

Baby Daisy Geyser

Baby Daisy is one of the exciting stories right now at Upper Geyser Basin, says Duffy. This geyser shoots water at an angle 25-30 feet into the air approximately every half hour. According to Duffy, this geyser hasn't been active since 1952 and briefly in 1959. The geyser can best be viewed from the highway near the bridge across the Firehole River, just south of Biscuit Basin. The geyser gets its name because its eruption is similar to that of Daisy Geyser, located a half-mile away. Duffy says a "datalogger" was recently installed near Baby Daisy that will tell geyser gazers more about its activity. Ask the folks at the Old Faithful Visitor Center for estimated eruption times for this geyser.

"What's neat about Baby Daisy is it's new and different," explains Duffy. It hasn't erupted since the 1950s and it brings the fun and excitement of change."

Butterfly Spring

This geyser is located in the Geyser Hill group. It can be reached by taking the boardwalk. It's located near Dome Geyser, right behind Old Faithful. After being dormant for some time, this little spring is again showing signs of activity, says Duffy. Recently it was sending muddy water 30-40 feet high.

This geyser's activity will probably be most meaningful to people familiar with the Upper Geyser Basin and who have been "waiting for something to happen," says Duffy.

A trip to Yellowstone's Upper Geyser Basin will not disappoint.

"What you'll see here is different from what you'll see in your backyard or in the rest of the world," says Duffy.