This is yet another world-famous destination to explore in Paris. The significance of the place lies in the fact that it holds a huge collection of bones and ossuaries under the city. The place was formed in the 18th century when the overpopulation of the cemeteries was a rising problem. More than 6 million people were moved to the ossuary. The place is really worth visiting. If you want to experience something unique on your trip then this is the place to visit. Here you can witness whole underground tunnels and caves filled with bones and skulls. This place is an ideal a spot for all the adventure lovers.