Travel deep inside of Europe's second largest glacier in the world's largest man-made ice cave.

A little-visited waterfall in an otherworldly landscape.

Two volcanic lakes in an enormous crater formed in a prehistoric eruption.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

A beautiful geyser under environmental threat.

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

One of the largest collections of wildlife art in the United States, built into the side of a cliff in rural Wyoming.

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

Native Americans built this circle of stones, which was used to predict astronomical events.

The crumbling structure is a rare surviving relic of the area's bygone mining industry.

A waterfall 600 ft. inside a mountain, once the bane of gold miners, is now a spectacle of nature.

This replica stave church looks like a piece of Norway was simply plopped down in South Dakota.

Thanks to a loophole in property ownership, this alleyway has become a cacophonous street gallery.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

A cave network located at the southernmost tip of mainland Greece was once believed to be an entrance to Hades.

An autonomous republic of Orthodox monks.

An alien landscape on the banks of the Aegean Sea.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

A small island with shimmering pink sands, home to loggerhead turtles and rare plants.

A beautiful 19th-century Armenian mansion is preserved above an unassuming cafe.

This hidden gem is bathed in beautiful natural light.

A Turkish monastery tucked into a cliff wall.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

This ancient mountain monastery welcomes all manner of faith in an effort to keep Christians in Syria.