Ice, snow and treacherous roads will be braved by seventy-two rally racers in a race to cross Russia the first.
Motors leaped into gear at the start of the race in Russia's north-western port of Murmansk.
Stamina is a must as the drivers strive to reach the eastern port of Vladivostok some 12,000km (7,456 miles) away in around two weeks.
The prize for the winner of the Expedition Trophy race is 10kg (22lb) of gold, reports say.
But the real winner is Russia, which is celebrating the opening last year of the trans-Siberian highway - the longest road in a single country.
The 36 teams - each consisting of two cars - will compete over seven stages, with several losers eliminated at the end of each stage.
Amateurs and corporate-backed teams from Russia, Ukraine, Latvia, Germany and the US are mixing it up to see who takes the longest to tyre..
They set off on Wednesday from a lighthouse near Murmansk and were expected later in the day near St Petersburg - where the race would begin in earnest.
A special train - with reporters and celebrities - will accompany the rally. A huge concert is planned on a frozen lake when the competitors reach the city of Irkutsk.
The race, which dwarfs the 7,821km-long (4,860 miles) Trans-Canada Highway and America's Route 66 from Chicago to Los Angeles, which spans for 3,862km (2,400 miles), truly puts Russia on the rallying map.
Andrew Zilouf
Russian Rally for Gold
The world's longest winter rally has set off in Russia.
