Loch Ness is a large, deep, freshwater loch in the Scottish Highlands extending for approximately 37 kilometres southwest of Inverness. Its surface is 16 metres above sea level. Loch Ness is best known for alleged sightings of the cryptozoological Loch Ness Monster, also known affectionately as "Nessie". It is connected at the southern end by the River Oich and a section of the Caledonian Canal to Loch Oich. At the northern end there is the Bona Narrows which opens out into Loch Dochfour, which feeds the River Ness and a further section of canal to Inverness, ultimately leading to the North Sea via the Moray Firth. It is one of a series of interconnected, murky bodies of water in Scotland; its water visibility is exceptionally low due to a high peat content in the surrounding soil.