This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

The largest game reserve in Africa is home to thousands of species but refuses to house humans.

Human-made caves excavated to hide a secret society of wealthy pagans.

The central mosque of this Mali town is entirely built from mud.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

A small town Romanian cemetery filled with darkly humorous gravestones.

A haunting statue called "Eternal Silence" has quite the reputation among visitors with active imaginations.

The first declared National Monument in the United States.

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

A bronze statue dating back as far as 1252, still has remnants of gold on its right cheek from ancient gilding.

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

Ruined castle with subterranean vaulted Goblin Ha' or "Goblin Hall."

Staves, storm-calling, and of course, necropants.

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

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

Siddhartha Gautama sat here and received enlightenment.

Malaysia's floating mosque.

Submerged ruins of a Neolithic coastal settlement, where houses, wells, graves and skeletons have been unearthed.

A blooming house of worship for the masses.

Experiencing Guatemala's sensory-exploding church is a blunt reminder of European influence.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

Sacred Indian temple that’s all monkey business.

This historic, palatial theater is now one of the world’s most beautiful bookstores.