Paris always has an answer for anything London does, and when it comes to catacombs they have over compensated once again. During the same period as London’s catacombs were built so too were holes being dug under Paris for disposing of the dead. Catacombs proved a cheap way for the lower class to lay their dead to rest. The bones of over six million decorate the walls of the main ossuary. The place is usually open for tourism when it isn’t being vandalized (the ossuary was closed in 2009 for such a reason). Have a look inside. Like London, there are many tunnels of different origins (with or without human remains) that fully constitute the “Catacombs of Paris”. One could spend days fully exploring the world below this modern metropolis.