155 paddlers from all over the world will gather in Canada's north-western Yukon Territory to compete in a gruelling 715km river race from Whitehorse to Dawson City.
Among the competitors are a 24 year-old Australian.
The event is the 17th annual Yukon River Quest, known as the 'race to the midnight sun' on June 24 2015.
Competitors from 12 countries have 55 hours to complete the race. All teams must complete the journey before midnight on 27 June.
The Yukon River Quest is the longest race of its kind, with just two mandatory rest stops along the way, and a sun that never sets. This is due to Yukon's position 60 degrees north of the Earth's equator.
Find out more about the Yukon River Quest.