Every hour on the hour a naked heroine and her leering foil appear from this giant cuckoo clock.

This amazing 15th-century mural remained hidden in plain sight for centuries.

A preserved block of timber buildings from the city's industrial era in the Middle Ages.

The world's largest military aircraft cemetery.

Artists have long been drawn to these atmospheric 12th-century ruins.

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

This nondescript building hides an entrance to an underground nuclear tunnel system.

The only pub in the world surrounded by an ancient stone circle.

This landmark overlooking Ramsbottom pays homage to Sir Robert Peel, repealer of the Corn Laws.

The commemorative stone column conceals a secret laboratory.

The little-known second castle that William the Conqueror built in York.

“And the Lord said unto Johan, build for thee an ark for the end of the world is approaching.”

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

From afar it looks like someone's hat blew into the water, but closer inspection reveals a giant floating sculpture.

An enormous Polaroid picture adds an artistic flair to Rotterdam.

A giant floating rubber duck-bunny painted with a different design every year.

A strangely curved lamppost stands tall over this avenue in Rotterdam.

A nearly 25-foot concrete sculpture of Sylvette, Picasso's muse.

Four giant movable street lights decorate this modern Rotterdam square.

A huge teapot illuminates a home for the elderly.

A modern reimagining of a medieval city gate.

This charming pup is meant to celebrate the youth and stubbornness of the city's students.

A dramatic art installation features a BMW flying out of a building in Rotterdam.

Built by crowdsourcing, this wooden foot bridge saved a part of Rotterdam that was languishing in wait of city funding.