The southern extremity of Llyn Brianne, a substantial reservoir in the upper Towy Valley which was constructed in the late 60s and early 70s to provide water for tinplate and steel works near Swansea. These have since closed, and the reservoir is now used to provide drinking water for towns along the coast of South Wales. Rock for the dam was quarried from the hillside above, which can be seen in the right of this photo, and clay was collected from higher up the valley. Although it doesn't look particularly spectacular, at 300ft this the the highest dam in the UK.