The lakeside town of Thun is suddenly illuminated, casting a dazzling reflection on the water. This view probably dates from Turner’s final trip to Switzerland in 1844. He used a remarkable variety of techniques to create the dramatic effect. Thread-like lines of pen and red ink give shape to the rooftops and the turreted castle, while pink, grey and blue watercolours are overlaid to evoke the menacing storm clouds. The distant mountain peaks, loosely brushed in with blue, may be the Eiger, Mönch and Jungfrau.