One of Scotland's most important modern structures, it just made the '100 Most Endangered Sites' list.

This castle was established by the 4th Duke of Montrose and is connected to the Buchanan Clan.

Stonehenge has nothing on Castlerigg’s views.

One of the highest Roman forts in Britain is set amid dramatic scenery on a notoriously difficult road.

These Roman ruins in England’s Lake District are 2,000 years old, but look pretty good for their age.

Although it appears ancient and mysterious, the quirky folly was actually built 200 years ago by an eccentric estate owner.

A modern English garden of eccentric beasts, follies, and oddities.

A dramatic sculpture high up in Yorkshire with vistas on an industrial scale.

A group of glacial erratic boulders are improbably balanced on white limestone pedestals.

This incredible viaduct was part of the Victorian railway boom and helped the Midland Railway navigate tough terrain.

A steep and winding road in the Yorkshire Dales passes by these deep natural potholes.

These remarkable cascades are the jewels of Upper Tees.

This section of the Kennet and Avon Canal has been designated the same level of heritage protection as Stonehenge.

A lone pole once used to display a man's corpse now stands empty, but the memory remains.

Possibly the oldest living thing in Europe, more likely a pagan survivor.

Legends say this red sandstone monolith and the dozens of smaller boulders that surround it were once a coven of witches—before a Scottish wizard turned them all to stone.

This temple was constructed entirely by Roman soldiers.

Also known as “Robin Hood’s tree,” it became a famed location along Hadrian's Wall before it was cut down.

These quaint cottages feature built-in signaling devices for fishermen.

More stones than Stonehenge, all scattered within a windswept landscape sure to enchant 'Outlander' fans.

This Neolithic-era complex boasts standing stones, a cairn, and the only henge in Western Scotland.

This collection of Neolithic monuments make up one of The U.K.'s richest archeological landscapes.

A small island abbey is the final resting place of many medieval Scottish monarchs, including the real Macbeth.

The last manually operated turntable ferry in the world.