The Midway Geyser Basin's Grand Prismatic Spring is the largest hot spring in Yellowstone and one of the largest hot springs in the world. Measuring approximately 370 feet in size and around 121 ...

How the Grand Prismatic Spring Gets Its Kaleidoscopic Colors The beating heart of Yellowstone National Park is without a doubt the Grand Prismatic Spring—the largest hot spring in the U.S.

While a one-day visit can showcase the highlights, a 3-day Yellowstone itinerary is ideal for most travelers, encapsulating top sights like Old Faithful, Grand Prismatic Spring, and the Grand ...

Ever been mesmerized by the swirling colors of Grand Prismatic Spring and wondered what fuels that otherworldly boil? It turns out that beneath the wild expanse of Yellowstone National Park lies ...

Editor’s Note: This story accompanies the May 2016 issue of National Geographic magazine, devoted entirely to America’s first national park. Find more at natgeo ...