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

One of the shortest streets in York has an especially odd name.

This network of narrow, medieval passages has the most delightful name.

In England, an 18th-century water-powered workshop still stands.

In the ancient Woolley Woods, an art project promises access to new worlds.

The whimsical steel spider lurking in the shadows of this suspension bridge shows that engineers can have a sense of humor.

A brick foundation and piles of listing building materials are all that remains of this World War II POW camp.

One of the last doorless, continuously moving elevators still in use in the U.K.

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

There's a labyrinth of medieval chambers hidden deep below a 15th-century pub.

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

These lovely Turkish-styled baths were brought back to life after winning a reality show competition.

"The Donut" was built as part of an expensive, ill-fated engineering endeavor.

A quartet of rusting satellite goliaths are all that remain of a communication network that protected Britain from German and Russian air strikes.

A medieval cave used to shelter local hermits now holds nearly 200 old Quaker gravestones.

This early Norman castle was the first historical monument protected by an act of Parliament.

A mysterious bridge over a sunken Roman road.

One of the oldest and certainly best preserved Cistercian abbeys still in existence.

Once thought to be the mysterious work of a witchy prophetess, a well with unusual properties turns objects into "stone".

Artists have long been drawn to these atmospheric 12th-century ruins.

This haunting stone chasm is a hotbed of mossy rock and English legend.

This tiny little pool is said to be home to a malicious mermaid named Jenny Greenteeth.

Some wattle-and-daub, a Moorish mural, a glacial erratic, and a Giant named Gilbert.

An ancient woodland that inspired a young J.R.R. Tolkien.