A once-glowing grotto at the bottom of Waikapalae Wet Cave.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

Experience a charming 1930's version of "infotainment."

Watch the newest land on the planet form before your eyes.

These picturesque Hawaiian falls are home to a rare species of fish that uses a special sucker to climb up cliffs.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

A desert ghost town—occupied for only 12 years—was once home to more than 500 silver mines.

This historic national park is covered in the stunning ruins of red rock pueblos.

One of the largest, oldest, darkest, quietest motel rooms in the world.

See massive fossils that are over 200 million years old in northeastern Arizona.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

A beautiful geyser under environmental threat.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

The tallest waterfall in the Judean Desert is named for its connection to a biblical figure.

As the Dead Sea continues to deplete, massive sinkholes open along its banks.

This amazing ancient cave was kept secret for seven years to protect it from the public.

This daunting 1st century fortress was purportedly the site of one of the most dramatic revolts of the Jewish-Roman wars.

The world's oldest known salt mine.

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

An Austrian house of bones filled with hundreds of intricately painted skulls.

This hanging crocodile is thought to be the "dragon" that once plagued a Czech city.

Mysterious painted skulls in Moravia.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.