Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

An accidental trick of light casts the perfect shadow of a pilgrim of the Camino de Santiago against the cathedral wall.

This enormous censer uses a pulley system installed over 400 years ago.

Scattered throughout London are ancient remnants of the city's former bounding wall.

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

Hear the quietest sound from across the dome.

Eighty million natural history specimens call this gargantuan museum home.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

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

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

Half-sized replica of the Leaning Tower of Pisa built to honor Galileo.

One of the few remaining relics of the meatpacking hub that made Chicago the "hog butcher to the world."

Once at the center of U.S. finance, the historic Trading Room was meticulously recreated piece by piece and rebuilt in the Art Institute.

This awkward aquarium sculpture is one of the strangest statues in Chicago.

This surprising gem is a world-class archeological museum hidden at the University of Chicago.

Once called the "Polish Gold Coast" it is an icon of the neighborhood that bears its same name.

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

In Chicago, a pizza-enthusiast has opened a museum dedicated to the history of pizza.

This modest post office sits on the site of H.H. Holmes' famous murder castle.