The biggest orienteering event in the UK is getting under way in Surrey, with 3,000 athletes due to compete in four days of events in the South East.
Graham Gristwood will be competing on home ground in Surrey
The UK's top competitors are racing against those from Europe, Australia, Japan and the United States in the JK International Festival of Orienteering.
The first event, at the University of Surrey in Guildford is on Friday.
Other races are taking place in the Ashdown Forest, East Sussex and Tunbridge Wells, Kent.
The British number two, Graham Gristwood, 23, who grew up in Woking, Surrey, said he was retuning to the areas where he learnt orienteering.
"I started with my father when I was very young, so have been doing it all my life," he said.
"But every course is unique, so even if you back to the same place, the course setter will have planned a different race."
Orienteering involves a timed race with a map. Competitors have to go round set checkpoints in the fastest time possible.
The weekend's participants, ranging in age from five to 85, are starting with a sprint event.
On Saturday, there is a middle and long distance race, taking place all day at Leith Hill, in Surrey.
Sunday sees another all-day race in the Ashdown Forest and Monday a relay in Erridge Old Park, Tunbridge Wells.
Gristwood said he was ranked about 30th in the world but wanted to improve his position this year.
"There is some good competition from abroad and all the best British guys are here, but I have been training well so I hope to get some good results," he said.
Friday's, Saturday's and Sunday's events also include courses for beginners, which people can enter on the day.