Llyn y Fan Fawr Llyn y Fan Fawr Llyn y Fan Fawr (Welsh: 'lake of the big peak') is a natural lake in the county of Powys, Wales. It lies at the foot of Fan Brycheiniog, the highest peak of the Black Mountain (Welsh"Y Mynydd Du") range within the Brecon Beacons National Park. Created as a result of glacial action, it is one of the largest glacial lakes in southern Wales. The lake is roughly rectangular in shape with its long axis oriented roughly north-south. The surface of Llyn y Fan Fawr lies at about 1815 feet or 605m above sea level. Its primary
Pen-y-Gwryd Plas y Brenin. The Old Miners' Track from the Snowdon copper mines are now part of the modern A4086 road between Pen-y-Gwryd and Pen-y-Pass. It continues northwards beyond Pen-y-Gwryd skirting Glyder Fach to Bwlch Tryfan and Dyffryn Ogwen. From Pen-y-Pass is the "PYG track", one of the many routes leading to the summit of Snowdon, its name is believed be derived from the initials ("P-y-G"). However, older maps show it as the "Pig track", a name derived from "Bwlch y Moch" (the Pigs' Gap). During Roman Britain, the Roman Army built a marching camp at the head of Dyffryn Mymbyr