This luxury shopping lane has been protected by its own tiny police force for over a century.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Pop culture has helped to keep this iconic British building from being destroyed.

Charles Babbage's proto-computer, painstakingly brought to life.

The Columbia Road Flower Market is now open every Sunday, rain or shine.

This 1920s Dutch barge is now a floating bookstore.

This hidden green space is the city's second largest conservatory.

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

The Metropolitan Police refurbished the blue box (perhaps not coincidentally) the same year "Doctor Who" returned to TV screens.

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

Giant, friendly pelicans in Central London, the most unlikely of places.

The sixth of London's "Magnificent Seven" cemeteries, and a source of unlikely inspiration to Beatrix Potter.

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

Eighty million natural history specimens call this gargantuan museum home.

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

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

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

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

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

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.