Australians famously like to celebrate Christmas on the beach. For most people in the northern hemisphere, however, Christmas is a time for staying inside, preferably close to an open fire or at least some efficient central heating. If you do have to go outdoors, then wrapping up well is advised.

Not everyone thinks that way, however. Across Europe, a minority of enthusiasts -- some would say eccentrics -- take part in annual outdoor swims on Dec. 25 or 26, braving sub-zero temperatures to prove their virility, raise money for charity or for the purported health benefits of icy water.

With its long coastline and tradition of eccentricity, the UK is unsurprisingly home to many Christmas swims. Perhaps the most famous is the annual race in the Serpentine lake in London's Hyde Park, which has been held every Christmas morning since 1864. The 2006 race was distinguished by being won by a woman, Sally Kelly, for the first time ever. The aptly-named Bournemouth Spartans winter sea swimming club also organizes a Christmas Day swim for members, who range in age from 10 to over 80.

In Wales, a record number of 583 people took part in a swim on Boxing Day (December 26) in Tenby, while around 700 swimmers took to the sea in Porthcawl, the BBC reported. Porthcawl swim organizer Dai Thomas said one man had been treated for suspected hypothermia. He emphasized this was only the second case in the annual swim's 41 year history.

Even in northern Scotland, swimmers brave the chilly North Sea. In the northern village of Burghead -- which is on the same latitude as Alaska -- a record 96 people took part in a Boxing Day swim, according to Scottish daily The Press and Journal. The annual swim has raised GBP 150,000 ($294,000) for charity in its 21 years.