Geocaching is a GPS-aided combination of hide the Easter egg and orienteering for internet nerds. I have logged >700 caches since 2005 and had lots of fun.
Borås Tidning now reports about a not terribly thoughtful geocacher. He had placed a cache in a space locked with a combination lock. Part of the puzzle was to figure out the combination. So far so good.
The locked space was a sealed 650-meter utility tunnel excavated through bedrock for a sewage line at a depth of up to 10 meters below ground surface. And the sewage tends to leak hydrogen sulfide, which makes the tunnel a potentially lethal place to be unless you’re carrying a scuba-diving tank. And before locking the hatch to the tunnel with his combination lock, this geocacher removed a conventional padlock whose key was held by Mark municipality.
Don’t try this at home, kids.
Update same evening: The kids who placed the cache have spoken to the newspaper, claiming that a) they found the hatch rusty and unlocked, and b) there was no sign suggesting that the tunnel was dangerous. Municipality staff do not challenge these statements, but contend that the kids should have understood that they were not allowed to enter the tunnel. As far as I can tell, there is no solid evidence for how dangerous the atmosphere in the tunnel really is.
Thanks to Niklas Krantz for the tip-off.