Cool Must See Tourist Attractions

Grand Prismatic Spring, Yellowstone National Park

Ditch the tourist crowds at Old Faithful and head to Yellowstone's secret star, the Grand Prismatic Spring. Approximately 370 feet wide and 121 feet deep, Grand Prismatic is the largest hot spring in the park and the third largest in the world. The water may look tempting, but don't dive in—it's around a scalding 160 degrees. The stunning colors are caused by different species of pigmented bacteria, photosynthesis, and refracted light.

The Colosseum (Underground), Italy

Rome's Colosseum, an ancient amphitheater and former gladiator battleground, is one of the world's most famous attractions. But most people don't know that there's a whole secret section that can now be explored—the underground. In 2010 the Italian government decided to allow small groups of visitors inside the Colosseum's subterranean level to see where gladiators made their grand entrances from and their final exits (at the Porta Libitina, the arch through which bodies were removed). Visitors can also see where exotic animals like lions and tigers were held below ground before being hauled up in elevators to appear suddenly before the screaming crowds.

Pamukkale, Turkey

The bright blue pools of Pamukkale in Turkey look as if they're sitting atop piles of snow or cotton (hence the name, which is Turkish for Cotton Castle), but in reality the natural pools and terraces are formed by calcite deposits. The thermal pools, with temperatures of around 95 degrees and a number of healing minerals, are thought to have therapeutic qualities, so be sure to take a dip in the Sacred Pool if you visit. Ancient emperors and kings used to vacation at the pools here, so you’ll be bathing in history.

Racetrack, Death Valley, California

It's a mystery of the desert: In an isolated valley between the Cottonwood and Last Chance mountain ranges, the Racetrack features rocks that appear to be moved by a secret force. The rocks sit on a playa (dry lakebed) and move across the flat surface, leaving trails in their wake. According to the National Park Service, some of the large rocks have traveled up to 1,500 feet, but no one has ever actually seen them move.by caroline morse