The nearly 200-year-old folly has a secret spiral staircase hidden in one of its pillars.

A relic of Victorian grandeur hides beneath a busy South London road.

This former abandoned hospital, a complex of stunning 19th century buildings, once housed 2,000 psychiatric patients.

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

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

A petite castle folly in the English countryside.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

Local legends say that fairies used to dance in the moonlight here and invite handsome young men into their grottoes.

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

There's an exclusive Beefeaters pub hidden in the Tower of London.

One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

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

The largest oak in England is said to have been the hideout of Robin Hood and his Merry Men.

Eyam took steps to quarantine themselves and keep the plague from spreading.

The sculpture is made of more than 100,000 knives collected to raise awareness about violence.

The granddaddy of English geoglyphs dates back to the late Bronze Age.

In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

A open air theatre built on a cliff by an eccentric British woman.

The ruins of an 11th-century Norman castle with a rare, perfectly circular shape.

Stonehenge has nothing on Castlerigg’s views.

This beautiful "lagoon" is actually a toxic soup filled with cars, carcasses, and trash. When warnings couldn't stop people from going for a dip, the town dyed it black.

The forest that inspired Winnie-the-Pooh's Hundred Acre Wood can be found outside London.

J.R.R Tolkien, C.S. Lewis, and other "Inklings" met at the Oxford pub to discuss the now legendary fantasy stories they were writing.

This crumbling folly looks like an enchanted left over from Middle Earth.