Fan y Big Fan y Big Fan y Bîg ( is a subsidiary summit of Waun Rydd in the Brecon Beacons National Park, in southern Powys, Wales. It is high and is often hiked as part of the Horseshoe Walk, a traverse of the four main peaks in the Brecon Beacons. At , Fan y Bîg lies at the western tip of the Gwaun Cerrig Llwydion plateau. Its name translates as 'Point of the Peak' - perhaps in allusion to its striking pointed shape, as seen from some directions. The summit is smooth and grassy, but marked by a cairn, which stands on
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