This crumbling industrial fortress has attracted daredevils, filmmakers, and historians.

An 800-year-old island castle in Guernsey's main harbor.

Underground hospital complex constructed by slave laborers during the German occupation of the Channel Islands.

An intricately decorated tiny place of worship.

The first island in the world designated a light-pollution-free astronomical observation point.

Eighty million natural history specimens call this gargantuan museum home.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

Hidden in a grotto 26 feet below Nottingham's oldest hotel, this stylish subterranean drinking den is notoriously hard to find.

A striking 500-year-old mansion provides an unexpectedly sublime home for live deer and a menagerie of exotic stuffed animals.

A labyrinthine underworld of tunnels and caverns hides beneath the city.

The oldest inn in England served brew to the crusaders.

The remains of a Dominican friary, once one of the largest of its kind in the United Kingdom.

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

This century-old grotesque has a mysterious history and may not actually be a rabbit.

This building was once a town hall, a fire station, a prison, a dairy market, and the target for two marksmen.

A perfectly running 230-year-old silver automaton and music box.

A monument with a strange legend involving a horse's tongue.

An unusual stone chair can be found on the banks of the River Wear, not far from Durham Cathedral.

Hundreds of years ago, this lion-shaped door knocker could help a person accused of a crime find temporary safe haven in Durham Cathedral.

A rather grand, but tiny, folly on the banks of the River Wear associated with a Polish count.

These lamps were created to expel sewer gases after an event known as The Great Stink.

The 2,000-year-old pieces of metal are an ancient soldier's military discharge papers.