Paris doesn't have lots of tall, heavy buildings in its centre and for good reason. This is because of a large underground cemetery stretching over nearly 11 square kilometres.
This burial site contains around 6 million skeletons placed all over the tunnel walls. Among the buried, you will find the ashes of some prominent Frenchmen including Jean de La Fontaine (author of Fables), Charles Perrault (famous for fairy tales like Cinderella, Little Red Riding Hood, and Puss in Boots), the painter Simon Vouet, and the sculptor Francois Girardon.
The catacombs were originally limestone quarries back in the 13th century. In the 18th century, the tunnels were used for burying Parisians owing to the rapid population growth, and hence the lack of room for above-ground cemeteries. Since the 19th century, this spooky underground attraction has been drawing large tourist crowds even sometimes resulting in long queues to get in.
This strange attraction is available year-round, but if you want to find the shortest lines, avoid the Christmas holidays, school holidays, and the summer high season. The best time is from September to mid-December, and from January to May. To reduce your waiting time it's better to plan your visit in the afternoon, from Wednesday to Friday.
Try to avoid standing under the sun for over an hour. We hope the video below convinces you better than our words.