An unfinished tomb carved into a giant boulder in the Arabian Desert.

The angel of death appears to weep black tears at this grave marker.

Natural cathedral designed by Italian artist Giuliano Mauri.

New York City's smallest piece of private property.

The tallest residential building in Africa is an unsettling Brutalist monolith.

Stunning examples of Russia's 18th-century wooden architecture.

A sacred mountaintop temple offers a fine cup of tea to visitors who can survive the journey.

Perched on a spindly rock spire in a Greek archipelago, this lighthouse would make a perfect wizard's tower.

An abused and forgotten metropolis, abandoned for centuries.

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

A salty red wasteland in Tanzania is a breeding spot for endangered flamingos.

The hottest place on the planet.

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

On the outskirts of a desert trading village high on the Andean plain, steel giants have been destroyed by salt winds.

A part of the world's largest marsh seems to be growing bright red Martian grass.

A dangling church built over a Colombian gorge.

An enormous concrete structure built over a nuclear crater.

Because sometimes the most efficient route from A to B isn't a straight line.

A solitary tree has grown up all alone on Lake Wānaka, backdropped by the beautiful Southern Alps.

This hidden stream beneath Indianapolis makes an appearance in the best-selling novel "Underground Airlines."

A 605-page Quran penned in the blood of a dictator is locked away in a mosque.

The remains of a monument in the remote Kazakhstani desert dedicated to the only men to die in outer space, the crew of the Soyuz 11 rocket.

One man's swirling six-acre monument of stone.

A series of five defunct panopticon prisons in Cuba.