Pwll y Wrach

Pwll y wrach or Pwll-y-wrach is a feature on the River Ennig near Talgarth in south Powys, Wales.
It is 17.5 hectares of beautiful ancient woodland, which slopes down to the banks of the River Enig. Near the eastern end of the reserve the river plunges over a spectacular waterfall into a dark pool below, known as the "Witches Pool" from which the reserve gets its name.
Wikipedia