it's known as the 'Blue Lagoon', but the flooded former quarry near Buxton hides a toxic secret.
It's so polluted that it's almost as toxic as bleach.
There are warning signs that state the water can cause skin and eye irritations and stomach problems, but people continue to swim there.
More top news
This evening an image of Salman Abedi taken from CCTV on the night he committed the attack, has been released
The Duke of Cambridge also laid a wreath to honour the victims before kick-off.
The mother of one of the Manchester attack victims has told of the distressing moment she found her daughter being treated after the attack.