Mounds of fine golden sand that can rise nearly 500 feet tall.

In 1909, the steepest and most difficult piece of track on the Canadian Pacific Railway was replaced with a series of spiralling tunnels cut into the mountains.

Ute tour guides have been sharing the ancient dwellings and rock art inside this large park with visitors for more than 40 years.

The best-preserved beehive tombs in Oman with spectacular backdrop.

The tallest mud-brick structure in the world has been standing since the 1500s.

The second-longest continuous wall on the planet protects a hidden secret in the deserts of India.

Lions carved into the rockface adorn these two tombs built into the mountains of Dadan.

The ruins of a 2,000-year-old Roman fishing village perched on one of the best beaches in Spain.

This reconstructed Norman castle is the world's most accurate, from location to livestock.

A long strip of fossil-filled limestone makes up this natural bridge above a rushing stream.

An ancient city exhumed from the depths of the ocean.

The world's largest bioluminescent area was undiscovered by science until 2005.

Bioluminescence in the reefs of the Maldives causes the sea to glow like a starry night sky.

Once the center of power for the region's various factories.

For this chef, an active volcano is his oven.

An unusual slot canyon in the Aztec/Navajo Sandstone has a cross-section like an inverted old-fashioned keyhole.

The sinister ruins of one of the worst dam failures of the 20th century lie in this astonishing alpine setting.

The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

A swath of France so devastated by war it is still forbidden to go there.

You can find America's highest suspension footbridge at Grandfather Mountain in North Carolina.

Inside this Krakow church, an explosion of psychedelic color.

These unique stepping stones hug a river's edge to take hikers on a journey through a limestone gorge.

Red sandstone structures dominate this landscape, which has been inhabited for some 5,000 years.

An abandoned suspension bridge on the Falkland Islands is crumbling into the water.