Looking strangely like Rome's Colosseum, this unfinished tower has dominated the skyline for over 100 years.

The most northern place on the mainland of Great Britain.

The ruined abbey includes a rare surviving example of a monastic latrine.

Home to the longest wooden escalators in the world.

This 15th-century structure had a long, tortuous journey to its current location.

A giant sculpture of the legendary "Salmon of Knowledge" celebrates the return of fish to Belfast's River Lagan.

This hidden gem reveals the history of Britain's first police force.

At this snack-shack in the bucolic British countryside, you can still get a slice of socialism with your spot of tea.

The oldest of the three remaining bridges in England with buildings on top of them.

The beautiful non-repeating pattern honors the Oxford professor who discovered it.

A hidden sculpture garden tucked within the middle of Brighton.

A historic holy well hidden near a charming English park.

The UK's oldest theme park slowly slips away.

Tucked away behind the mansions of Mayfair, this picturesque garden is a hidden London treasure with a spooky past.

The sign announces the Scottish village's cosmic connections, as it's twinned with Glenelg, Mars.

Scotland's first free lending library, which protects literacy through inheritance.

Inside this art museum resides one of Glasgow's most famous musical instruments.

This iconic Peak District ridge was once one of the busiest roads in medieval Britain.

More than a century old, this cast iron bridge on the Balmoral Estate leads to nowhere.

This abandoned hospital village was once viewed as an innovative way to deal with mental illness.

Wander around the extensive remains of this 12th-century medieval church.

Forgotten jail cells beneath this Scottish town hall are now used for delightfully artful storage.

This lighthouse was crafted as penitence for the theft of wine bound for a monastery.

A boulder in the Churchyard of Down Cathedral marks the legendary burial place of "The Apostle of Ireland."