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

An artistic tribute to the famous singer, just around the corner from where he was born.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

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

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

A Victorian natural history and ethnographic museum with wonderful turn-of-the-century, science-book-esque evolution displays.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

London's smallest police station is barely the size of a phone booth.

Eighty million natural history specimens call this gargantuan museum home.

Catacombs turned marketplace.

Hear the quietest sound from across the dome.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

Rebuilt remains of a temple to Roman god Mithras.

One part local history, 99 parts gruesome haunted house.

A hands-off space for graffiti artists to hone and display their skills.

An unusual round church in London with a Templar past.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

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

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

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

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

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.