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.

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 ...

Formed over thousands of years of erosion caused by hydrothermal activity, water and other natural forces, the Grand Canyon of the Yellowstone is the primary attraction in the Canyon Village area ...