A Victorian Gothic masterpiece housing a world-class collection of rare books and manuscripts.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

Giant, friendly pelicans in Central London, the most unlikely of places.

Abstract dinosaur models in London.

A historic London cemetery now serves as a nature park incorporating gravestones & memorial statues.

London's old-school healing garden.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

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

The signs of a long buried road can still be found hidden beneath a London sewer grate.

Every day is like Christmas on this street where the traditional Neapolitan nativity scene comes to life.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

This ancient market is often referred to as the oldest shopping mall in the world.

This large, circular tomb is the final resting place of the first emperor of Rome.

In Rome’s Jewish ghetto, a 200-year-old bakery still makes the neighborhood’s historic sweets.

A forgotten "city of water" underneath the famous Trevi district.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

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

This hidden Art Nouveau courtyard is an opulent feast for the eyes.