After 400 years of being closed to the public, this monastery's underground tunnels and secret garden are now a museum.

This ruined castle is said to be the legendary keep of a Viking princess.

Human-made caves excavated to hide a secret society of wealthy pagans.

Luxurious hotel designed to stir the imagination of its many visitors.

The sixth of London's "Magnificent Seven" cemeteries, and a source of unlikely inspiration to Beatrix Potter.

This long-hidden space above Westminster Abbey now displays the battle gear of the legendary King Henry V.

This coffee shop lies hidden beneath a historic church.

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

These morbid carvings remind churchgoers of the inevitability of death.

London's old-school healing garden.

In this cobwebbed old operating theater, you can practically hear the screams of the unanesthetized patients.

This 1920s Dutch barge is now a floating bookstore.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

This Norman castle was once the site of a Victorian-era prison, and now exists as a luxury hotel.

A rare survivor from the age of plagues.

It's believed King John of England stayed at this 13th-century castle before riding off to sign the Magna Carta.

At this historic pub, you can sit back, sip, and watch a whole century go by.

Grab a cuppa at England's first and only domestic tea plantation.

Hidden on a cobblestone street in Glasgow, a Czech Cajovna-inspired teahouse serves as a hangout for Bohemians.

A historic shipbuilding town is home to a sail-through fish-and-chips shop.

This historic pub has maintained much of its 1906 decor, including a small sequestered room for women, where orders were slipped through a tiny window.

Come for the oysters, stay for the priceless art honoring inventors across history and Scotland's favorite outdoor sports.

Now home to a drinking establishment, this building has a macabre history.

This centuries-old pub boasts a collection of more than 4,500 snippets of neckties from around the world.