Lake, Highland council area, Scotland.
It is 788 ft (240 m) deep and about 23 mi (36 km) long and has the largest volume of fresh water in Britain. It forms part of the Caledonian Canal system developed by Thomas Telford . On its shores are remains of two fortresses. Surface oscillations, or seiches, caused by differential heating, are common. Reports of an aquatic monster inhabiting Loch Ness date back centuries but remain unproved.