This giant wooden treehouse within a sprawling garden has its own eatery.

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

This magical museum celebrates the life and work of a seminal children's book writer (and occasional spy).

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

The oldest candy store in the world has been selling traditional sweets since 1827.

The secret wartime bunker built on the platforms of an abandoned Tube station.

The majority of the museum's large collection is held in a storage space open to the public a few times a year.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

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

The first geometric self-supporting spiral stairs in Britain are a truly beautiful sight.

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

Installed at a chaotic intersection, this gave London traffic cops a place to hang their heavy woolen coats.

A century-old tradition has culminated in a small but singular collection of feline effigies.

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

Ship-sized kinetic sculptural fantasy.

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

The rose garden in Regent's Park where Pongo and Perdita met for the first time in Disney's "101 Dalmatians."

On this wooded path, a stained-glass window creates a spellbinding forest cathedral.

No one knows who created the statues or if they are arranged properly—let alone the artwork's real name.

This overlooked street light once served as a KGB dead letter box.

Never actually a tree at all, this spot was the site of London's public hangings for nearly 600 years.

These morbid carvings remind churchgoers of the inevitability of death.

Drink your espresso at a Victorian-era urinal in this underground-restroom-turned-coffee-bar.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.