Three New Zealanders have entered the world's longest and toughest horse race, over 1000km across Mongolia.
Charlotte Davison, Dave Murray and Hannah Ritchie will be among about 25 riders set to race across the Mongolian plains from August 22, each of them changing horses every 40km.
The race has beenframed around the communications system used by Genghis Khan, a kind of pony express using a relay system which was able to get a message from Mongolia to Eastern Europe in just 14 days, organisers said on their website.
The modern-day riders will use 800 horses, each of them finding their own route across Mongolia.
The riders from New Zealand and eight other countries range in age from 24 to 65, with the New Zealanders all aged in their 20s.
A former British jumps jockey who is competing, Richard Dunwoody, predicts the race will be "incredibly tough".
Each rider will also have to raise 1000 pounds ($2646) for a charity, Mercy Corps, and many are also raising money for other charities.
Ms Davison said she had already raised the 1000 pounds and was now raising money for research into a screening programme for early diagnosis of pancreatic cancer, which killed her grandfather, and recently, her father.
Mr Murray, who works for an American oil company in Western Australia, said he planned to travel with a maximum 10kg of supplies. He spent August last year riding a motorbike through five countries in South America.
Ms Ritchie said she had competed in eventing, and had recently been working giving physical therapy to injured racehorses being re-trained as riding hacks.
