Taken from the Guinness World Records site:
On 5 June 2010, 25-year-old Eric McNair-Landry (Canada) and 46-year-old Sebastian Copeland (USA/France) kite-skied 595 km (369.72 miles) in 24 hours, covering the distance between on Greenland. The duo established the record speed on day 23 of a 43-day expedition to cross the 2,300-km-long (1429-mile) Greenland icecap from Narsarsuaq in the south to Qaanaaq in the north. They used 14-m (46-ft) Yakusa kites for most the 24-hr period, reaching speeds of 60 km/h (37 mi/h) and beating the previous record of 507.5 km (315.35 miles) by Hugo Rolf Hansen and Bjørn Einar Bjartnes (both Norway) set on 2 July 2009.
Copeland’s diary entry for the day concludes: “We will reap the reward of our labor with a day off, a glass of electrolytes and a bowl of granola and water! Don’t be jealous, now!”