https://www.nationaltrust.org.uk/cy/visit/wales/bannau-brycheiniog-brecon-beacons/crwydro-pen-y-fan-a-chorn-du
Dringwch ddau gopa uchaf de Prydain neu ddarganfod llwybrau cerdded anghysbell yng nghrombil Bannau Brycheiniog.
pen y fannational trustducymru