Thirlmere. The Lake District
Thirlmere is a body of water in between Grasmere and Keswick with the Helvellyn ridge along the East side of the Lake. The valley was dammed in the 19th century to provide water to Manchester, the water is gravity fed all the way there. The dam is located at the north end of the water.
From the water you get great views up to the Helvellyn ridge which fills the skyline. Thirlmere also has a few small islands which change throughout the seasons depending on the water level. The water level can also reveal the remains of the Wythburn at the south end of the water.
views of Thirlmere are also great from the surrounding fells. My favourite is from Helvellyn and the descent down towards Helvellyn. You get a full view of the water whilst looking in the direction towards Keswick. This is also a good location to catch the sunset.