A little-known ruin with a convoluted history and a fascinating latrine drainage system.

A famous pilgrimage site that remains hidden in the midst of a city.

This Roman archeological site is hidden amid a 1930s housing estate.

This gorgeous space is England's largest independent library outside of London.

The largest timber structure in Europe.

One of England's oldest stone churches and the birthplace of the "father of English history."

This steel sculpture made from a recycled crane towers above a former shipyard.

The train that took the prime minister on his final journey now rests in a British museum.

Rare remnants of the brick-domed ovens birthed in the Durham coalfield during the Industrial Revolution.

The world’s oldest surviving single-arch railway bridge.

The nearly 200-year-old folly has a secret spiral staircase hidden in one of its pillars.

This Georgian Gothic building was created to shelter and feed deer.

A remarkable feat of Victorian engineering across the Firth of Forth.

An iconic waterwheel in the Pennine Hills marks the location of one of Britain’s most profitable lead mines.

Take afternoon tea in a 17th-century almshouse.

This medieval manor house was hastily fortified when it found itself in the middle of the Scottish fight for independence.

This temple was constructed entirely by Roman soldiers.

These ruins of a medieval church are full of architectural mysteries.

The one-time stronghold of the noble Douglas family, now home to ghost sightings and nesting birds.

The remains of the observatory of the Danish astronomer who first measured the speed of light.

Built after WWII, the observatory site for the University of Copenhagen exhibits once world-class instruments.

This Denmark theme park is part family attraction, part experimental archaeology project.

A perfectly circular stronghold constructed in the 10th century is now a nucleus of Viking culture housing a museum, village, and reenactment of an epic Viking battle.

Considered one of the most haunted places in Europe, this 800-year-old castle was home to noble prisoners.