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

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

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

A community of artists and entrepreneurs seeks a simpler life on London's waterways.

These morbid carvings remind churchgoers of the inevitability of death.

Public access to clean drinking water was an instant hit among the masses.

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

Where condemned pirates met their grisly end at the gallows on the River Thames.

Eclectic final resting place of the controversial explorer.

This landmark church concealed a crypt packed with bones that was discovered thanks to the London Blitz.

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

This secluded walkway overlooks a magnificently wild London green space.

A Roman spa buried deep beneath the City of London.

Remnants of cells from the most notorious London prison may lie in the basement of a rare Victorian Gin Palace.

This home on a quiet suburban street is completely covered with vibrant mosaics.

A naturally mummified 2,000-year-old man.

This beautiful Victorian ironwork masterpiece was built to keep London from smelling like poop.

Following the trail of an old metro line, this scenic path is haunted by a creepy spriggan statue.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

An small and easily overlooked archaeology museum chock full of Egyptian artifacts.

The largest of London's subterranean rivers and once a mad, bad center of London life.

A mysterious pair of mice eating a piece of cheese is London's smallest public sculpture.

A closed London rail station created to cart away the dead still bears the marks of attempts to make it less morbid.

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