This didn't make international news, so I only have link to the french version of
that story Résumé :
on december 18, 2004, the man went into an undergroung quarry, previously used as a mushroom nursery : he was depressed and simply wanted some solitude. But in the kilometers of underground passages, he rapidly get lost.
Nobody knew where he was. His wife rented a helicopter to fly over the woods, where he could have been walking...
After more than a month, college kids found his car in the entrance of the caves and alerted authorities.
They rapidly (1h30) found him (he calls when he heard noises), about 200m only from the entrance.
No need to say he didn't have any PSK, nor watch, nor light.
He spend these 35 days drinking water and eating decomposed wood ! lost 18kg.
The first week he tried to find the way out, without success. Afterwards, he spend most of the "days" lying on old plastic sheets he had found.
After a few hours at the hospital, he has been sent back home.