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"Paris was crowded in the late 1700s. It had a burgeoning population clamoring for housing and burial plots. To free up valuable real estate and remove the healt"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/lifestyle/eco-tourism/photos/explore-the-catacombs-of-paris/danger-of-collapse>