A hidden tunnel of bones in one of Malta's oldest churches.

The bones of prehistoric animals and early signs of human habitation have been found inside Malta's "cave of darkness."

Ancient mysterious ruts carved in the bedrock.

Despite the name, these small saltwater swimming pools have nothing to do with the Romans.

The eclectic seaside sanctuary caters to a rather fowl crowd.

Malta’s oldest sea water distillation building is now an architectural anomaly on the Sliema waterfront.

This sculpture, residing in a quiet corner of a London park, honors the victims of 9/11.

This is Bremen’s oldest historic district, famous for its labyrinth of narrow medieval alleys lined with tiny, colorful 15th-century houses that resemble beads on a rope.

A traditional American farmhouse plopped in the middle of a Piccadilly courtyard.

One of the greatest movie directors of all time lived and worked in this London flat from 1926 to 1939.

The next-door homes of two very different musicians, George Frideric Handel and Jimi Hendrix.

A configuration of a trio of statues that depict a scene reflecting a time emblematic in the city’s rich history.

Heralded as the oldest statue in London.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

The handiwork of a underdog clockmaker who solved an impossible problem for an Empire, and forever revolutionized seafaring.

These stained-glass windows are all that remains of a building that was the target of one of the biggest explosions in London after World War II.

This landmark church concealed a crypt packed with bones that was discovered thanks to the London Blitz.

The taxidermied remains of a once-great parrot.

Museum dedicated to the UK's first charity for abandoned children, with keepsakes of the mothers who left them behind.

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

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

A bare tree in Riga’s Esplanāde is transformed into an extraordinary vertical neighbourhood by scores of colourful bird nesting boxes clustered across its trunk and branches.

The Underground railway station and its Cubist/Art Deco statue are so evocative of 1920s/30s London that one almost expects to see Poirot on the stairs.