An abandoned tank sits in an empty London lot as a symbolic middle finger to local city planners.

One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

An ancient water supply dating back almost 500 years can still be found standing in East Sussex.

This centuries-old hotel hides a network of secret cellars and passages once used by smugglers.

Where condemned pirates met their grisly end at the gallows on the River Thames.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

A glorious pub known for a spiteful printing feud and its famous typeface lost—then found—at the bottom of the Thames.

London's marvelous wildfowl reserve along the Thames.

No one knows who created the statues or if they are arranged properly—let alone the artwork's real name.

This beautiful deer park was built so King Charles I and his court could go hunting while escaping a deadly plague outbreak.

It is against the law to obstruct the view from the top of this English burial mound.

In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

A medieval replica of King Arthur's legendary table, the Round Table hanging in Winchester Castle was decorated by Henry VIII.

This silent sentry in the crypt below a large Gothic cathedral is often knee-deep in water.

"We gonna rock down to Electric Avenue, and then we'll take it higher..."

This ruined medieval castle was the scene of Lord Robert Dudley’s seductive reception for Queen Elizabeth I.

A beautiful ruin of a 14th-century Plantagenet castle built by a medieval mercenary.

The pedestrian traffic signals in Brazil's teeming metropolis light up with clues to nearby landmarks.

One of São Paulo's tight urban intersections has become a haven for graffiti artists ever since a single Batman started the trend.

This park feels like a lush little jungle full of wildlife nestled within São Paulo.

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

A historic London pub with prison cells in the cellar and a "spy room" on the second floor.

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

A monolithic monument in Greater London.