Russian adventurer Fedor Konyukhov, 65, on Monday took off in a hot-air balloon in Western Australia in a bid to beat the record time for a solo flight around the world.
The current record of 13 days has been held since 2002 by Steve Fossett.
Konyukhov and his team have been preparing for the challenge for close to a year.
The hot air balloon stands 52 metres tall and weighs 1,600 kilograms, although the adventurer will be confined to a pod not much bigger than himself in its gondola.
The flight path for his trip goes over Australia, the Tasman Sea, New Zealand, the Pacific Ocean, South America (Chile and Argentina), the Atlantic Ocean, South Africa and the Indian Ocean, before ending back in Australia.