Rainbow over Yellowstone’s Mammoth Hot Springs area. NPS / Jim Peaco Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. By signing up, you confirm you are 16+, will receive newsletters and promotional content and agree to our Terms of Use and acknowledge the data practices in our Privacy Policy . You may unsubscribe at any time. Last year, 4.8 million people ventured to Yellowstone National Park , one of the most famous of our nation’s “best ideas.” And it’s not surprising why. The park, spread across 2.2 million acres and three states, includes half of Earth’s active geysers, the Grand Canyon of the Yellowstone River, and stunning wildlife.  Ahead of the 2026 summer tourist season, Yellowstone National Park recommends following these 10 steps for making the most out of your visit. And remember what not to do when visiting any national park and to hold on to your hat .  Yellowstone’s famed Grand Prismatic Spring. Image: NPS / Jim Peaco.…