The highest pedestrian bridge in Singapore looks like a series of undulating waves rising between two public parks.

It's believed that this small church was connected to the Hagia Sophia via a secret tunnel.

The only Roman honorific column in Istanbul.

Have tea in a cemetery with a dazzling view of Istanbul.

This half-forgotten fortress was constructed by the Ottoman conqueror of Constantinople.

Climb a steep hill in 90 seconds on the second-oldest urban subway in the world.

Legend says if you stick your thumb in the hole and it gets wet your wish will be granted.

The most metal church of all time was built in record time because of an international, pious pissing contest.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

A marvel of Byzantine engineering under the streets of Istanbul.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

Turkish adventurer antiques in the heart of the Grand Bazaar.

1513 Turkish world map, full of European state secrets and snarky commentary.

An Art Nouveau gem hides beneath the layers of city grime obscuring this once-magnificent building.

A sixth-century Byzantine cistern hidden below a modern carpet store.

The ornate miniature mansions were built for Istanbul's feathered residents.

Writers such as Paul Bowles, William Burroughs, and Samuel Beckett frequented this Tangier bookstore.

This stucco building in North Africa was the first American-owned property on foreign soil.

An old airplane engine forms an unusual cairn atop this Moroccan peak.

Reaching this rock formation involves a hike through rocky rapids and springs where wild turtles reproduce.

This 16th-century Moroccan fortress-turned-armory museum offers prime views of the historic quarter in Fes.

The forgotten remnants of a land-to-sea cable car that was once unique in the world.

An eerie former warehouse turned cistern turned movie set.

Exploring the wilder, more passionate sibling of Erg Chebbi feels like discovering a secret sun-kissed planet from another galaxy.