A camper who went to the toilet in the dark fell 40ft down a cliff when she lost her way back to her tent.
The 22-year-old was without a torch as she fell at the Cae Du campsite in Rhoslefain, West Wales.
Friends raised the alarm at 2.30am when she did not return to her tent.
According to WalesOnline, an RAF search and rescue helicopter was sent and took the woman to Ysbyty Gwynedd Hospital in Bangor.
Glyndwr Davies, owner of the Cae Du campsite, told The Sun: "She got disorientated, missed her tent and went over the cliff.
"The lights for the toilets are always on all night. This has never happened before in the site's 100-year history.
"It's just purely accidental, I think."
A Wales Air Ambulance told WalesOnline: "Our Caernarfon-based air ambulance conveyed an adult female from Ysbyty Gwynedd, Bangor yesterday at 10:50am to Stoke hospital, arriving at 11:25."
She is recovering from her injuries at the hospital.
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