The Blue Lagoon reboot
A blue pool in a disused Derbyshire quarry that was popular with swimmers—despite being caustic from the quarry stone, and containing refuse and the remains of dead animals—has been dyed black to deter them. As one local observed, They don't think they're on holiday in the Bahamas any more, they know they're in Harpur Hill.
It's grim oop n'rth.