This programme digs beneath the streets of France’s capital to explore three extraordinary underground networks. The oldest, the catacombs, was created in response to the threatened collapse of ancient quarries under the city, as workers filled in cavities left by centuries of mining. In the late 18th century, human remains were relocated to the catacombs, creating an ossuary.
Next, we investigate the sewage system that Paris began building over a century ago to improve sanitation, which is now a labyrinth of pipes almost 3,000 km long. Finally, we explore the Metro, which grew from one line in 1900 to become one of the densest subway systems worldwide, and now carries four million passengers a day.
The catacombs, the sewage system, and the Metro – three massive projects that pushed the limits of underground construction
