Question: For which feat of endurance is the Norwegian explorer, photographer, writer and former deep sea diver for the oil industry whose diving was mostly carried out in a marginal sea of the Atlantic Ocean located between Great Britain and Scandinavia and whose name is Børge Ousland, best known?
Sentence (from "North Sea"): It is more than 970 km long and 580 km wide, with an area of around 570000 km2 .
Relevant evidence: No