The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

The last bastion of Roman presence north of the Alps looms over a German town.

The remnants of a record-setting industrial bucket system can still be found dotting the Swedish countryside.

A network of concealed passageways lies within a busy London Underground station.

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

Outside of one of Britain's most renowned social clubs, a step installed specifically for the Duke.

A haunting monument dedicated to the Royal Naval Air Service and the Fleet Air Arm.

This Underground station has been a popular filming location for decades, even before it closed.

The "beautiful" equation predicting the movement of all electromagnetic particles is engraved in front of Newton's tomb.

The next-door homes of two very different musicians, George Frideric Handel and Jimi Hendrix.

An architectural oddity hides in plain sight on this iconic London bridge.

The Tudor-style cottage in the middle of the square is not quite what it seems.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

This unique bridge curls up like a caterpillar to let boats pass and then unfurls again to span a small canal.

The fierce beast perches atop a pedestal marking where the historic City of London gates once stood.

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

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

This London marker celebrates the spot where the world-famous English band was founded.

A portly statue of a golden boy commemorates an unusual cause of the Great Fire of London: the sin of gluttony.

A unique tribute to the millions of animals who served and died for the British military.

The last remaining example of the boatmen's perches that once dotted the south bank of the Thames.

These ornate arches show how the course of the River Thames has changed.

A monument to the thrice mayor of London who according to lore made his fortune by selling his rat-chasing cat.

Spitalfields' regal market goat is said to be a monument to the area's migrant population but most are pretty sure it's just a goat.