Thousands of pieces of art have been carved into the rock at the site of an ancient volcanic eruption.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Steep canyon walls hide a forested oasis in the West Texas desert.

The highest point in Texas is capped by a big silver pyramid.

The remnants of an abandoned, 19th-century gold mill along Aruba's rugged northeastern coast.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

The beautiful baroque library of the Hapsburg empire.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

When a medieval fire claimed the original St. Stephen’s Cathedral, it sparked a pattern of unquenchable organ building.

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.

In Northeastern Iceland lies something of an oxymoron: a steaming desert.

This stunning concert hall has become a symbol of Iceland's national recovery.

The bright red stripes streaking across the rocks are the star feature at this Icelandic waterfall.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

The most powerful waterfall in all of Europe.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Iceland's largest lagoon is home to stunning multi-colored icebergs.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

The once highest point in China blends symbolic design with a kick of adrenaline.

Hidden behind musical flora and forgotten for over a thousand years, this cave is now a neon dream.