Four teenagers had to be rescued after getting lost in a mine complex for about six hours while hunting for creatures on the Pokemon Go phone app.
The boys, thought to be aged around 14 or 15, were only saved when they eventually managed to contact Dorset and Wiltshire Fire and Rescue from the bottom of a 100ft ventilation shaft at Box Mine, in Wiltshire.
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A local guide who knew the mines was drafted in to help and the four were rescued unharmed at about 6pm on Thursday, station manager Damien Bence said.
Pokemon Go, an augmented reality game, was launched in the UK on Thursday and has exploded in popularity - it uses the phone's GPS location data to allow players to roam the real world and catch virtual monsters.
Mr Bence told the Press Association: "They were a bit reluctant to say why they were down there - one of them did mention they were looking for Pokemon characters.
"I asked him 'did you find any?' and he said 'no'."
Mr Bence said the firefighters were unable to go into the mines and called on a specialist mine rescue team but a local guide offered to go down and lead the boys out an hour after they made their emergency call at 5pm.
"They said they got in there on Thursday lunchtime, around noon, so they had been lost for around five hours.
"They miraculously got a phone signal at Cathedral, an old ventilation shaft 100 feet below ground, and called us at around 5pm.
"This ventilation shaft is quite near a few domestic properties so we started making contact with them. We sent water down and a radio so they could talk to us.
"One guide offered to go down with our rope rescue. They were only 100m from the nearest exit but they just could not get to it."
The fire service issued a warning not to go into the mines without a guide and Mr Bence said it was "craziness" that youngsters were putting themselves at risk by playing the game.
"It's a massive mine complex - it's one of those places where you need an experienced guide as there's a junction almost every five paces," he said.
"I think it's about 72 miles of tunnels - they are quite fortunate."
The rescue comes after two men suffered minor injuries after falling off an ocean bluff in southern California while playing the game.