Underwater ice hockey (also called sub-aqua ice hockey) is an extreme sport played upside-down underneath frozen pools or ponds, where participants wear wetsuits and flippers and use the underside of the frozen surface as playing area for a floating puck. Finland won the first Underwater Ice Hockey World Championships held in Lake Wessensee in Austria in 2007, and now Austria the second held in 2013. See facebook.com/IcehockeyUnderIce