British soldiers jump into the icy water in Estonia.

British soldiers serving in the battle group of NATO's reinforced forward presence in Estonia ended the traditional winter course with an ice bath.

100 British soldiers practiced orienteering in the cold, survival skills and how to escape from an ice hole.

The instructors were mostly Marines who had undergone Arctic training in Norway.

The winter course lasted three days. Before taking an ice bath, the soldiers walked 7 kilometres, also using snowshoes.