Malham Tarn
Scenic National Trust lake in the Yorkshire Dales featuring the Malham Tarn Field Studies Centre. At 377 metres above sea level, Malham Tarn is the highest marl (calcium carbonate or lime-rich mud) lake in Britain. A short walk around Malham Tarn beneath the looming cliffs of Great Close Scar offers ramblers a chance to experience a variety of habitats, from craggy limestone bluffs, to thick forest, peatland and a wildlife-rich upland lake.