One of the world's more unusual extreme sporting tournaments is underway on the Arctic island of Svalbard - ice golf.
Coloured balls are a must for ice players (picture: Svalbard Wildlife Service)
The Norwegian Spitzbergen archipelago is hosting the sixth world ice golf championship, 1,000km (621 miles) north of the Arctic Circle.
Armed guards will protect the golfers from roaming polar bears.
A nine-hole course has been built especially for the occasion near the Advent Fjord and participants use coloured balls for the icy fairways.
They wear thermal suits to stay warm as temperatures may drop to -30C. Players are also required to break for lunch in a heated tent between rounds due to the cold.
Other unusual, but mandatory, equipment includes rifles in case of polar bears. Tinted goggles are also a must to guard against snow blindness.
With regards to more conventional pieces of golfing equipment, players are urged to use clubs with steel shafts, as graphite tends to shatter at extreme temperatures.
The Spitzbergen town of Longyearbyen boasts two indoor full swing golf simulators and is home to what is possibly the world's northernmost golf club.
The tournament gives local players a welcome break from indoor playing.
Arne Kristoffersen, of tournament sponsors Svalbard Wildlife Service told the BBC News Website, that conditions were great for golfing with temperatures at only -4C degrees as the tournament got underway.
Still, he warned, finding a golf ball buried 20cm deep in snow might prove a challenge, despite the ball's bright orange colour.
"We are playing in the evening," Mr Kristoffersen said. "Although the midnight sun is still about a week away, the sun barely dips below the horizon at night."
The Spitzbergen archipelago was only identified for the first time in the late 16th century by the Dutch explorer Willem Barents.
Due to the very real risk of polar bear encounters it is the only part of Norway where one can legally carry firearms.