This sublime architectural marvel is a rare example of an expressionist church.

This World War II airfield enjoys a second life as a public park.

Macabre symbols of death and mummies on display set the tone of this Italian purgatory church.

The oldest-known example of a historic architectural style recognized by UNESCO.

Southern Italy's spinning top village.

Skulls and skeletons are omnipresent in this church dedicated to souls trapped in purgatory.

People have been living in the cave houses on this Italian hillside since the Neolithic era.

An abandoned quarry hides an open-air gallery of huge sculptures, some made from the rubble of 9/11.

An eccentric artist's abode in this small Italian town has been transformed into a surreal temple of mosaic madness.

This 19th-century island fort built to protect against an invasion by sea.

Also known as "Robin Hood's tree," this tree became a famed location along Hadrian's Wall before it was cut down in an act of vandalism.

Buy your fish and have it cooked to order in this bustling, eight-floor seafood market.

One of Australia's largest collections of preserved animals is on display in a historic theater.

Hundreds of people walk past this palm tree every day without spotting its secret.

This Western Australian mint was established during the height of the Australian gold rush.

Catacombs turned marketplace.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

The final resting place to 300 Victorian-era pets hides inside the city park.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

This iconic high-rise residential block was one of the last to be built in the Brutalist style.

This "floating railway" is one of the world's oldest monorail systems.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

There are many Byzantine-era churches still standing in Athens, but this is the only one with a 2,500-year-old column rising through its roof.

The ruined doorway is a portal to the building's turbulent and torturous past.