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

Rare collection of medieval books under lock and key.

This beautiful system of tunnels built into natural rock serves as a centuries old plumbing system.

Death rituals and sacrifice inside a Peruvian megalith.

Huge stone depressions which may have acted as an Incan agricultural experiment.

The hallucinogenic center of the ancient world.

Ancestral Puebloan ruins, natural arches, and box canyons abound in this seldom-visited corner of Monument Valley Navajo Tribal Park.

Mirrors and glass shards cover every inch of this arrestingly beautiful mosque.

This ancient burial site is believed to be one of the first earthquake-protected structures in the world.

This lost city belongs to one of the earliest civilizations in the world.

This legendary city has been a tourist attraction for centuries.

Preserved Inca city and site of the last Inca stronghold against the Spanish conquistadors.

The palace of the King of Kings, burned by Alexander the Great.

Putrefaction plateaus in Iran, where the dead were sent for decontamination before going to their final resting place.

Catacombs turned marketplace.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Detailed sandstone carvings show an array of symbolism and adorable animals.

This well-preserved Cistercian Abbey in a romantic pastoral setting has inspired artists like the poet Wordsworth.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

This shop for all your super spy needs hides an educational secret.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

A terrific purveyor of natural history objects and curios.

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