The first tunnel to be dug beneath a river, repurposed as an art and museum space.

Three small rooms at the back of the “official” church of London's clowns.

Murals of the wild parties once held on the frozen River Thames.

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

A sculpture outside London's oldest cathedral honors the Mohegan chief who died while petitioning the king.

A quiet, semi-secret square with statues of Mahatma Gandhi, Virginia Woolf, and a conscientious objectors stone.

The sculpture of the deceased cockatoo flops atop its personal plinth.

These morbid carvings remind churchgoers of the inevitability of death.

The grand complex of buildings that comprise Liverpool's Exchange Flags includes a vast World War II bunker that has been frozen in time.

A memorial to the politician who became Great Britain's first fatality to be caused by a locomotive.

A collection dedicated to the treatment of disease, held in London's oldest hospital.

The final resting place to 300 Victorian-era pets hides inside the city park.

A unique tribute to the millions of animals who served and died for the British military.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

A living memorial to the trees London lost during the Great Storm of 1987.

London's smallest police station is barely the size of a phone booth.

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

A traditional American farmhouse plopped in the middle of a Piccadilly courtyard.

Pyramid shaped monument with a tall tale attached.

Prehistoric sandstone menhir with Early Bronze Age cup and ring markings, also known as Robin Hood's Stone.

A thousand year old oak tree survives in Liverpool.

Gutted during the Liverpool Blitz, this architectural husk has been left destroyed in honor of the dead.

The Liverpool street made famous by the Beatles is real.

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