This medieval castle was reconstructed by Carlo Scarpa.

Not far from the more famous House of Juliet, visitors will find the supposed residence of her lover.

A gorgeous example of 13th-century Gothic architecture.

Pilgrimage site for star-crossed lovers.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

This massive library holds what was once the largest book collection in the world.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Abandoned railway line circling the city of Paris.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

The remains of Crystal Palace Great Exhibition of 1851.

The remains of the great moral philosopher reside in a university in London.

A Victorian natural history and ethnographic museum with wonderful turn-of-the-century, science-book-esque evolution displays.

A cluttered and astounding collection of antiquities and curiosities.

This hidden green space is the city's second largest conservatory.

Rebuilt remains of a temple to Roman god Mithras.

Hidden beneath the streets of London is a secret subway that only carried mail.

One of the largest underground systems runs under Canada's largest urban center.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

Wild West history in Hollywood style.

This opulent hotel has been visited by Spider-Man, Charlie's Angels, and the Ghostbusters.

A multimedia experience that chronicles the atrocities of racism.