Climb atop one of the world's longest and heaviest trains for an unbelievable journey across the Sahara Desert.

The second largest monolith in the world was once betrayed by its lover, Ben Aicha.

This mountaintop lake bubbles and steams in a perpetual boil, thanks to its direct link to the Earth's interior.

Fabulous formations, weird and wonderful wildlife.

Over two-thirds of the world's population of giant tortoises live among this coral formation.

This geometric feat is a testament to the Incas' mesmerizing architectural abilities.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

Huge stone depressions which may have acted as an Incan agricultural experiment.

Preserved Inca city and site of the last Inca stronghold against the Spanish conquistadors.

A set of ancient drawings in the desert of Peru that are so massive, many of them can only be fully seen from the sky.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

Pyongyang’s Arch of Triumph is the second tallest triumphal arch in the world.

A highly symbolic tower in honor of Supreme Leader Kim Il-sung's personal philosophy.

A symbol of the Workers' Party of North Korea.

A bizarre collection of gifts to North Korean dictator Kim Jong Il from the despots of the world.

Rimmed by white crusts of salt on every edge, Lac Assal is one of the saltiest bodies of water in the world.

Ethiopia's "smoking mountain" is in one of the hottest regions on the planet and is home to two lava lakes.

The explorer Captain Cook may have named it White Island, but the Maori call it Te Puia o Whakaari – The Dramatic Volcano.

Underwater volcanic eruption forms new island off the coast of Tonga.

Plains of ash and pair of semi-active volcanoes contribute to the otherworldly beauty of this little-known Vanuatu island.

This South Pacific volcano has been blowing its stack for over 800 years and is said to be home to a cult leader waiting to be reborn.

Erotic art covers the walls of the largest ancient pleasure palace.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

The world's most active stratovolcano is almost always erupting.