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

A naturally mummified 2,000-year-old man.

The television series' iconic giant foot was borrowed from this classical painting.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

This coffee shop lies hidden beneath a historic church.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

This marine reptile was discovered by one of the 19th century's greatest fossil hunters.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

Helen Keller once broke ground on this historic center for the study of technologies to benefit the hearing impaired.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

Rome's ancient Etruscan rival, now a park full of ruins.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

Architectural monsters are devouring this palace's every door and window.

Richard Luke Concanen never set foot on American soil.

The sacristy of this church contains remains and relics of members of the Aragonese royal family.

The remains of the left arm of the levitating philosopher-saint are kept in a 13th-century Neapolitan basilica.

An unusual "skull with ears" sits in the crypt of this small church tucked away at the end of a narrow alley.

Before it was buried by volcanic ash, this fast-food restaurant fed the hungry hordes of ancient Rome.

This amazingly well-preserved villa just outside Pompeii boasts rare examples of ancient Roman paintings.