Anyone that suffers with claustrophobia, look away now. The nightmarish moment a man became stuck in a cave as it started filling up with water has been caught on camera.
The potholer was exploring Lost John's Cave on Leck Fell in Lancashire when water began flooding in, reports the Metro.
A man's headcam captured the scene as they started racing towards the entrance but, in the rush, one of the men becomes stuck down a narrow rock tube.
The footage was uploaded to YouTube, and, according to news.com.au, one of the men wrote: "Worst caving experience ever... it took another three hours of crawling to get out the cave a different way."
Caving - also traditionally known as spelunking in the United States and Canada and potholing in the UK - is the recreational pastime of exploring wild (generally non-commercial) cave systems. In contrast, speleology is the scientific study of caves and the cave environment.
The challenges involved in caving vary according to the cave being visited, but, in addition to the total absence of light beyond the entrance, often include the negotiation of pitches, squeezes, and water hazards (as scarily demonstrated above). Cave diving is a distinct, and much more hazardous, sub-specialty undertaken by a small minority of technically-proficient (and daring) cavers.
In an area of overlap between recreational pursuit and scientific study, the most devoted and serious-minded cavers become accomplished at the surveying and mapping of caves and the formal (though usually private) publication of their efforts.
Would you be daring enough to try it? We're not so sure.
But if you are a bit of daredevil, try one of these top holiday activities: