When we're asked to picture the perfect beach, most of us would think of clear blue water gently lapping white sands.
So it's little wonder that locals find it hard to resist taking a dip in the lake on Harpur Hill in The Peak District - known locally as the Blue Lagoon.
But the Daily Mail reports that this water-filled disused quarry (pictured) is actually a toxic heath hazard - and visitors are ignoring warning signs explaining that the high pH levels mean that the water is almost as powerful as amonia or bleach.
Signs warn that the polluted water can cause skin and eye irritations, stomach problems, fungal infections and rashes - and that it's known to contain car wrecks, dead animals, excrement and rubbish.
Nevertheless, the Daily Mail reports that parents have been taking their children to swim in the lake, even though beer cans, glass and plastic bottles, condoms and syringes have been spotted near the water's edge.
Although the water looks inviting, the turquoise blue colour is caused by the surrounding limestone rocks, which leach chemicals into the water.
"It was one of the hottest days when I went last year, and the water was still freezing, at the end of day it's a disused quarry and it's stupidly deep.
"The water's littered with cars and large sharp objects and you sink into the lime sand stuff and can get stuck easily.
"My opinion, I loved it, I'm going to go again, but be warned - it's a very dangerous place."
Now that the Blue Lagoon is becoming something of a tourist attraction, the county council are looking at ways to clean up the area.
The Daily Mail reports that Pam Reddy, the area's county councillor, said: "Both councils are pursuing different possible long-term solutions with possible permanent solutions being the quarry being drained or filled in.
"Before this can be considered and undertaken full research has to be completed on flood risk and site drainage and then a full planning application would need to be completed and submitted."
Councillor Carol Hart, Derbyshire County Council Cabinet Member for Public Health, added: "I would just like to assure residents that at Derbyshire County Council we are doing all we can to help resolve this real problem. It is complicated by the fact that this is private land but nevertheless we will continue to work to come up with a solution to tackle this awful situation."
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