Foel Fraith Brecon Beacons, 11 April 2010 at 08:30 hours. This photograph was taken on a walk over the Carmarthen Fans, a number of hills, collectively called 'The Black Mountain'. The hill in the distance, Foel Fraith (1975 feet) , was the second of the day. The whole area has loads of sinkholes; depressions in the ground formed by the limestone being dissolved away. Camera details: 10-20mm, 1/4 sec at f / 22