Rhaedr Ddu or Black falls is a nice waterfall of 20 meters plunging down over 2 steps. The name Black falls is derived from the black stone over which the waterfall plunges down.
From Ganllwyd it a short walk through the Coed Ganllwyd National Nature Reserve, at the Coed-y-Brenin Forest, to the waterfall Rhaeadr Ddu in the river Afon Gamlan.