National Parks Facts

Mammoth Cave in Kentucky is the longest cave system on Earth - over 400 miles of tunnels. In 1842, Dr. John Croghan moved 16 sick patients underground, convinced that cave air would cure their illness. At least five died inside. Nearly all the others died within weeks of leaving. The doctor died of the same disease in 1849.

Yosemite ran a real fire waterfall for nearly a century. On summer nights, workers built a bonfire of red fir bark at the edge of Glacier Point. At 9pm, a caller shouted, "Let the Fire Fall!" Workers then pushed the embers off the cliff in a 3,000-foot cascade of flame. The Park Service banned it in 1968, calling it "as appropriate as horns on a rabbit."

Jhonatan Gonzalez was hiking the Narrows at Zion National Park with his family - kids as young as 1 - when the calm river suddenly turned waist-deep and raging, choked with logs and debris. He and his brothers planted themselves in the current and formed a human chain. Strangers on the bank grabbed on. Dozens of hikers, including toddlers, passed hand-to-hand to safety. Everyone made it out.

Mount Rushmore has a secret: a 70-foot granite tunnel cut directly behind the faces. Sculptor Gutzon Borglum began drilling it in 1938 to house America's founding documents for future civilizations. Congress shut the project down in 1939 and Borglum died in 1941. In 1998, his family lowered 16 porcelain panels into a titanium vault and sealed it under a 1,200-pound granite capstone. Nobody can go inside.

Death Valley is the hottest, driest place in North America. In February 2024, record rain turned its lowest point into a temporary lake called Lake Manly. It stretched six miles long and three miles wide, but only a foot deep. Death Valley has no outlet to the sea, so a lake this size almost never forms. People still grabbed kayaks and paddled across it.