This lonely tomb is all that remains of a once-bustling ancient trade hub visited by Marco Polo.

Nature's water park in the Wadi Bani Awf valley is full of pools flanked with cliffs and natural water slides.

Groups of prehistoric tombs that dot the mountains of northern Oman.

Some claim these desert ruins are from the legendary "Atlantis of the Sands."

An imposing Omani fortress surrounded by date palm trees.

This spectacular mosque houses the second-largest chandelier in the world.

The convergence of two currents makes this a surprisingly pleasant getaway in the Arctic Circle.

Home to three historic ships from the age of Vikings.

This "preacher's pulpit" once used for pagan ritual, is home to a new, and dangerous ritual.

An intricately carved Viking church overlooks a glistening fjord.

This giant boulder is pinched over a 1000-meter abyss by two mountains.

A serpentine highway twists and turns over the treacherous Norwegian Sea.

Walk 2,300 feet above the ground on the "Troll's Tongue."

This fortress dates back to the 6th century and is also the site of a controversial abandoned restoration project.

This 3,800-year-old site contains markers used to study the movement of the sun and moon and create a lunar calendar.

Space-age monument to an early 20th-century uprising.

Ado Awaye Mountain and the unique lake that sits near its peak are shrouded in ancient legends.

This igneous rock monolith towers above the surrounding landscape just outside the Nigerian capital.

The world's most remote memorial to the victims of the UTA Flight 772 disaster.

These ancient giraffes are the largest known animal petroglyphs in the world.

Volcanic activity causes small pools of super-heated mud to boil furiously.

The youngest volcano in Central America.

Tubing through a cave lit with glowworms is a magical underground experience.

One man's dream has turned into this naturally growing chapel made of almost nothing but trees.