Llyn Cwm Llwch both Pen y Fan and Corn Du and indeed from the spur of Pen Milan to its west. Llyn Cwm Llwch Llyn Cwm Llwch () is a small lake or pool in the Brecon Beacons National Park in Powys, Wales. It is between 1 and 2 acres: much smaller than the two glacial lakes in the west of the Black Mountain (range): Llyn y Fan Fawr and Llyn y Fan Fach. It is of glacial origin, occupying a rock hollow beneath the peaks of Pen y Fan and Corn Du in the central Brecon Beacons. It is drained by the
Pen y Gaer stone can be seen, as can those of a chevaux-de-frise. The entrance is to the west, and access can be gained from a car park, reached by the road from the village. Pen y Gaer Pen y Gaer (or Pen-y-gaer) is the location of a Bronze Age and Iron Age hillfort near the village of Llanbedr-y-Cennin in the Conwy valley, Wales. A natural defensive site, it had a long history of occupation, indicated by the complexity of the defences, which were amended over time. There are two Bronze Age cairns on the north-west slope, and extensive prehistoric and later field