Paris' underground , the catacombs, had been closed to the public after being vandalized. It has now reopened.
The creepy collection of human remains — cleared from city cemeteries long ago — is orderly, with bones piled in stacks along underground tunnels. Vandalism last year changed all this with bones and skulls scattered along the walking paths.
The catacombs are a vast underground network tunnel of tunnels holding the bones of more than 6 million Parisians. Near the end of the 18th century, Paris' cemeteries were filled to capacity, so city officials decided to transfer the contents of graves to quarries.
The section open to the public is only a sampling of the secret world: More than 300 kilometers (186 miles) of tunnels like beneath the city. The catacombs are visited by 257,000 tourists each year, according to city historical officials.
For more on the catacombs and travel to Paris, check out Open Road's Best of Paris.