No ground-level photo prepares you for what Grand Prismatic Spring actually looks like. At 370 feet across — the largest hot spring in the United States — its rings of orange, yellow, green, and blue come from heat-loving bacteria thriving at different temperatures. The overlook trail from Fairy Falls parking area is the move. Trust us on this one.
© Carsten Steger, CC BY-SA 4.0, via Wikimedia Commons