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

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.

Since 1887, this old-school shop has stacked its shelves with extraordinary coffees and teas.

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

This wildly-tiled artist's palace is a living and growing account of the creator's life, loves, and labors.

Hear the quietest sound from across the dome.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

This 1920s Dutch barge is now a floating bookstore.

A tongue-in-cheek arcade where the games are based on everyday life.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

A kaleidoscopic warehouse-maze of handmade neon signs.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Step into the cool deep past and unknown future of who begat who.

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

A diminutive statue that was inspired by the sculptor's own daughter.

The holes in this wall provide a glimpse into Jewish life in Budapest, both past and present.

The metal leaves on this tree are engraved with the names of Holocaust victims.

On Gellért Hill, this statue depicts the tragic tale of lovers divided by the Danube.

Time stands still at this serene burial ground in the center of Budapest.

A two-way chairlift system between Zugliget and the highest point in the city.

This quaint Hungarian railway system is operated exclusively by children between the ages of 10 and 14.

Tucked away near more famous landmarks lies a statue meant to symbolize the confluence and continuing development of human culture.