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

Historic cuisine meets fine dining in a hotel-restaurant overlooking Hyde Park.

This historic building displays the remains of a victim of the devastating 14th-century plague.

The commemorative stone column conceals a secret laboratory.

An archive of ceramic eggs painted to record clowns' personal makeup designs.

This marine reptile was discovered by one of the 19th century's greatest fossil hunters.

The fences outside some of South London's estates are made from recycled World War II stretchers.

An architectural oddity hides in plain sight on this iconic London bridge.

This beautiful deer park was built so King Charles I and his court could go hunting while escaping a deadly plague outbreak.

The pretty iron lamp is a reminder of the architecture underneath London's streets.

These ornate arches show how the course of the River Thames has changed.

This 19th-century pub features stained-glass windows celebrating Victorian-era "champions."

This coffee shop lies hidden beneath a historic church.

Originally built for London’s cab drivers, this bright green hut now serves anyone a hot drink or meal.

A decommissioned tube carriage within a London museum hosts a regular pop-up supper club.

The 2,000-year-old beam is tucked within the pedestrian entrance to the old London Bridge.

This Viking gravestone carved in a rare runic style was dug up from a London churchyard.

The remains of the great moral philosopher reside in a university in London.

The "lost friend” is the most famous of the six moai statues that were removed from Easter Island.

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.

This pub was 238 years old when it decided to revamp its image: It started serving Thai food.

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