This former quarry is now a picturesque gorge that hides a sunken lake.

This unique bridge curls up like a caterpillar to let boats pass and then unfurls again to span a small canal.

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

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

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

The monster at the center of the Darwin Center Spirit Collection.

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.

This secluded walkway overlooks a magnificently wild London green space.

The pioneer of psychoanalysis spent the final year of his life here, still seeing patients on that famous couch.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

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

A Roman spa buried deep beneath the City of London.

A hidden treasure in London with a rich medieval history, and the resting place of many luminaries.

Giant, friendly pelicans in Central London, the most unlikely of places.

The John Snow Memorial marks the epicenter of London's 1854 cholera epidemic.

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

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

London's old-school healing garden.

A Victorian natural history and ethnographic museum with wonderful turn-of-the-century, science-book-esque evolution displays.

An incarceration museum on the spot of possibly the oldest prison in England.

A special shop catering to the needs of things that go bump in the night, and also helps kids become writers.

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

A 1,215-foot tunnel transports pedestrians beneath the River Thames.