Two teenagers were rescued from Paris' catacombs after spending three days lost in the tourist attraction.
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The boys were treated for hypothermia after tracker dogs helped find them in a four-hour rescue.
According to the BBC, they went into the catacombs on Saturday night and the rescue effort was launched three days later.
Only a small part of the network of burial chambers is open to the public but people have been known to sneak illegally into the underground tunnels via secret entrances.
The teenagers, aged 16 and 17, were the first to ever get lost into the two kilometres of tunnels. It is not clear who raised the alarm.
A spokesman for Paris' fire service told the Guardian: "It was thanks to the dogs that we found them".
The catacombs are one of the most popular tourist attractions in Paris, where queues are often several hours long. The site holds the remains of more than six million people.