3000 km (1,864 mile) tunnel network that runs under much of the city. With public burial pits overflowing in the era of the Revolutionary Terror, the bones of six millions people were transerred to the Catacombes. The bones of Marat, Robespierre and their cronies are packed in with wall upon wall of their fellows citizens. This the empire of Death! The tour lasts approximately 45 minutes and the temperature in the tunnels is 14 °C.