19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

The barrel-made lookout from Shackleton's final ship is tucked away in the crypt of one of London's oldest churches.

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

The world's oldest optical museum is an odd collection where the exhibits look at you.

Catacombs turned marketplace.

This small museum in a former church crypt contains artifacts of the Elephant Man, Jack the Ripper and Florence Nightingale.

The lab where the scientist made his groundbreaking discoveries is preserved on the basement floor of the Faraday Museum.

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

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

A historic London cemetery now serves as a nature park incorporating gravestones & memorial statues.

This elaborate Byzantine-style building was designed for a not-so-pretty purpose.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

An artistic tribute to the famous singer, just around the corner from where he was born.

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

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

A plaque marks the underground site of one of London's "lost rivers."

Hidden beneath the streets of London is a secret subway that only carried mail.

The television series' iconic giant foot was borrowed from this classical painting.

Some of the earliest leaders of the Moravian congregation are buried here.

This hidden green space is the city's second largest conservatory.

London's only public statue of the much-married monarch adorns the gate to St Bartholomew’s Hospital.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

This South London cemetery holds the remains of more than 15,000 people.

Dictionary Johnson’s favorite feline.