A derelict bit of transportation infrastructure hidden in the woods.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

This forgotten boat elevator was an engineering marvel in its heyday.

The National Railway Museum in York is the largest railway museum in the world, attracting almost 1 million visitors per year.

Follow the original medieval paths that wind through this intriguing section of the city.

The little-known second castle that William the Conqueror built in York.

Cycle, walk, or run up and down on an old historic railway path.

The largest greenhouse in the world is home to over one million types of plants.

A giant roundabout made up of six smaller roundabouts can befuddle the uninitiated.

This crumbling 14th century chapel became so unstable the roofing apparently collapsed during a wedding ceremony, narrowly missing the curate's head.

This intriguing Bronze Age artifact spent centuries hidden within a Welsh faerie hill.

One of the oldest seagoing boats in the world can be found at the Dover Museum.

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

The ruins of a 12th-century Cistercian monastery can be found alongside World War II tank traps and pillboxes.

The site of London’s first coffee house has been serving refreshments of one kind or another for 360 years.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

Rebuilt remains of a temple to Roman god Mithras.

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

An exercise in radical design and social living that became the epicenter of Soviet spy networks in London.

The pioneer of psychoanalysis spent the final year of his life here, still seeing patients on that famous couch.

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

The majority of the museum's large collection is held in a storage space open to the public a few times a year.

This studio was home to David Bowie's first single, even if it did turn away the Beatles.

London's Victorian Tower of Babel.