Ice diving is a form of recreation diving that takes place in lakes that have been frozen over or other very cold places. Generally a hole has to be cut in the surface of the ice so that the divers can enter the water below. This adds a degree of risk to the dive as there is likely to be only one exit point available for the diver. Ice diving can offer the opportunity to see unusual sea life only found in the coldest environments. The relative dangers and complexity of ice diving mean that special training is required to undertake it. .