Perhaps the most spectacular grotto along the Algarve coastline.

This cluster of little wooden huts once ground local farmers’ wheat into flour during the days of the Austro-Hungarian Empire.

One of Antoni Gaudí’s earliest buildings, built between 1886 and 1890 for the industrialist Eusebi Güell.

This stunning iron gate designed by Modernist architect Antoni Gaudí is filled with mythic symbolism.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

One of the most spectacular canyons in the world.

Founded as a refugee camp, now a popular tourist spot.

It took 40 years to build this Eden-like garden in Marrakech, later restored by Yves Saint-Laurent.

Morocco's Argania trees are infested with nut-hungry goats.

Local lore says two enemy dragons live within these breathtaking mountain lakes.

An alien landscape on the banks of the Aegean Sea.

The hallucinogenic center of the ancient world.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

The "lost friend” is the most famous of the six moai statues that were removed from Easter Island.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

An eerie ship cemetery with gunfire as a soundtrack.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

Turkish adventurer antiques in the heart of the Grand Bazaar.

A marvel of Byzantine engineering under the streets of Istanbul.

Packed to the ceiling with antique taxidermy and hunting arms.

This once-grandiose behemoth of a monument from the socialist era now sits quiet and closed up.

UNESCO-protected ancient burial ground.

This historic black and white monastery is one of Bulgaria's architectural jewels.