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

A small island abbey is the final resting place of many medieval Scottish monarchs, including the real Macbeth.

Following years of secrecy, the hidden history of a World War II site is being brought to light.

This enormous secondhand bookstore inside a Victorian train station sparked the "Keep Calm and Carry On" craze.

This tidal island, a sacred site in early English Christianity, was the target of a notable Viking invasion.

A monument with a strange legend involving a horse's tongue.

A rather grand, but tiny, folly on the banks of the River Wear associated with a Polish count.

A million and a half tons of earth were used to create one of the world's largest land sculptures.

A giant piece of cutlery designed to remind us about the origins of our food.

Where artisans use centuries-old techniques to build traditional Arabian ships.

This beautifully restored fortification kept the city safe for centuries.

This bazaar is one of the oldest in the Arabian world.

This spectacular mosque houses the second-largest chandelier in the world.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

On any given day this sprawling market houses literally tons of government-regulated gold, gems, and precious metals.

The site of a bloody showdown between invading Iraqi forces and a cell of the popular resistance in Kuwait.

Kuwait City's uniquely designed water towers look straight out of a retro sci-fi cityscape.

Lived-in building, bedecked with an astonishing array of mirror mosaics.

This futuristic building is yet another architectural wonder in Dubai.

The world's largest frame offers spectacular views of the city's past and present.

Whitewashed mosque contains the world's largest carpet.

The colonial city's social history is reflected in its fanciful door knockers.

An inspired museum dedicated to the patron saint of enslaved people, inside the cloisters where he lived and died.

This elegant Colombian fortress was one of the torture headquarters for the Spanish Inquisition.