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Outdoors & Recreation

Grand Prismatic Spring

Midway Geyser Basin, Yellowstone National Park, Wyoming USA

  • Photo Op
  • Folk Art
  • Scenic Point
  • Natural Feature
  • Tourist Attraction
  • Roadside Attractions

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  • Independent
  • Credit Cards Accepted
  • Pet Friendly
  • Wheelchair Accessible
  • No Wifi
  • Street Parking
  • Private Parking
  • Restrooms
  • Outdoor Seating
April 10, 2014 Top Review!

The Springs are absolutely gorgeous from above, If you drive just past them, and hike up the hill behind you get an absolutely breathtaking view! It is also a great place to check out at night!

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Grand Prismatic Spring

Midway Geyser Basin
Yellowstone National Park, Wyoming USA

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The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world, after Frying Pan Lake in New Zealand and Boiling Lake in Dominica. It is located in the Midway Geyser Basin. Grand Prismatic Spring was noted by geologists working in the Hayden Geological Survey of 1871, and named by them for its striking coloration. Its colors include blue, green, yellow, orange, gold, red and brown, and recall the rainbow dispersion of white light by an optical prism.

The first records of the spring are from early European explorers and surveyors. In 1839, a group of fur trappers from the American Fur Company crossed the Midway Geyser Basin and made note of a "boiling lake", most likely the Grand Prismatic Spring, with a diameter of 300 feet (90 m). In 1870 the Washburn-Langford-Doane Expedition visited the spring, noting a 50-foot (15 m) geyser nearby (later named Excelsior).

The vivid colors in the spring are the result of pigmented bacteria in the microbial mats that grow around the edges of the mineral-rich water. The bacteria produce colors ranging from green to red; the amount of color in the microbial mats depends on the ratio of chlorophyll to carotenoids and on the temperature of the water which favors one bacterium over another. In the summer, the mats tend to be orange and red, whereas in the winter the mats are usually dark green.

 The center of the pool is sterile due to extreme heat.The deep blue color of the water in the center of the pool results from the intrinsic blue color of water, itself the result of water's selective absorption of red wavelengths of visible light. Though this effect is responsible for making all large bodies of water blue, it is particularly intense in Grand Prismatic Spring because of the high purity and depth of the water in the middle of the spring.

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June 16, 2014

Sunlight is a huge part in seeing the vivacity of the colors, wait out the clouds if you can!

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May 16, 2014

stunning. A must see while in Yellowstone!

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Rated 5.0 July 9, 2014

One of the coolest things to see if you're in Yellowstone! Absolutely stunning, definitely worth a visit.

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May 9, 2013

The springs have some beautiful colors surrounding it. Colors that you don't see in nature very often. Truly breathtaking.

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Rated 4.0 February 27, 2015

This geothermal spring is very soothing. I felt that my muscles were very relaxed when I took a dip in it.

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