Rome's catacombs were dug by members of a highly skilled guild of workers known as "fossores." The fossores dug the tunnels and chambers by hand using picks, carrying the debris away in baskets. They used light from a lamp or a skylight to see what they were doing. The fossores dug small chambers in the walls of the tunnels called loculi, where dead bodies would be placed.
In Naples, the catacombs were constructed in former stone quarries, meaning that the tunnels were much wider and larger than had been possible in Rome. Fossores cut the rock using the same tools and techniques as quarrymen.
The famous catacombs of Paris were also created in a former quarry. In the late 1780s Parisian cemeteries were completely full, to the extent that the pressure forced bones and corpses through brick walls into several cellars near cemeteries. Police Lt. Alexandre Lenoir had the idea to transfer more than 6 million sets of bones into the tunnels of the former quarries under the city.
