The curious underground history of keeping Paris clean.

Walk through spectacular aisles of hanging meat and wagon wheel–sized cheese at the world's largest wholesale food market.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

The history of radiation is on safe display at the foot of a radiation science laboratory.

A subterranean shelter remains intact under a busy Paris railway station.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

Notorious artist squat renovated into legal studios.

Abandoned railway line circling the city of Paris.

This former industrial site has transformed into a community sculpture garden that hosts monthly Full Moon parties.

The concrete shell of an industry giant remains as a playground for graffiti artists, auto scrappers, and paintball warriors.

Hamissi Mamba and Nadia Nijimbere opened this community-minded restaurant serving dishes from their native Burundi.

Detroit housing collective working to create an "environment for revolutionary change."

Glass and concrete building designed by Albert Kahn.

This railway-turned-greenway provides a pedestrian link in downtown Detroit and celebrates urban artwork.

The birthplace of the Ford Model T is now a museum full of antique cars.

38-story baroque tower reflecting Detroit's rise, fall, and possible rise again.

Dilapidated Mayan-themed ballroom was one of Detroit's most popular venues through the 40s.

Concrete igloos standing across from what remains of the Michigan Central train depot.

The grandiose interior of this bar speaks to its past as home to famous jewelers and railway offices.

Collective made up of artists, musicians, and activists.