Corn Du the last ice age by ice scouring out hollows below the peaks, the water being partly dammed by moraines of rock debris carried down by ice action subsequent to plucking and frost shattering. Corn Du Corn Du is a mountain immediately to the southwest of Pen y Fan and the second highest peak in South Wales at 873 m (2,864 ft), situated in the Brecon Beacons National Park. The summit itself is marked by a well structured Bronze Age cairn with a central burial cist like that on nearby Pen y Fan. The two summits are visible from great distances
Pen-y-Gwryd was developing in North Wales. In May 1898 "The Climbers Club" originated at Pen-y-Gwryd, as it is recorded in its first journal "...its natural birth at Pen-y-Gwryd" and "...its congenial atmosphere... ("The Climbers Club") first struck its roots". The "Climbers Club" is now based at "Helyg" on the A5 between Capel Curig and Ogwen Cottage. In 1870 the "Society of Welsh Rabbits" (c.1865) was founded with the objective of exploring Snowdonia in winter (and as close to Christmas as possible). Ann Owen said in 1895 that the society had written an article "praising Pen-y-Gwryd as an excellent resort at Christmas".