A floating cat sanctuary on an Amsterdam canal.

Cat art as far as the eye can see.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

A curious collection dedicated to human and animal anatomy and pathology.

Museum preserving torture methods from the past.

The eclectic home of a leading Turkish architect is a gorgeous piece of eye candy.

This former Imperial summer home was the venue for a royal slap that once echoed 'round the world.

Over the centuries, this island paradise has done it all, from providing monks with ecclesiastical respite to sheltering an exiled Leon Trotsky.

A meow-velous tribute to a beloved street cat, made famous on the internet.

This famous city eluded concrete detection until the early 2000's.

Roman ruins top white travertine terraces formed by ancient hot springs.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

The first American department store, and home to the largest operating musical instrument in the world.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Climb inside an iron crystal magnified 165 billion times its normal size.

One part local history, 99 parts gruesome haunted house.

An artist's cute bronze subway sculptures belie his violent artistic past.

This elaborate towering structure was once famed for its revolutionary height.

The most confusing clock in New York.