In Finland, divers learn to explore icy polar waters

Kilpisj rvi, Finland: In a square hole carved out of the thick ice, two divers vanished into the depths of an Arctic lake, leaving nothing but bubbles...

Kilpisjärvi, Finland: In a square hole carved out of the thick ice, two divers vanished into the depths of an Arctic lake, leaving nothing but bubbles at the surface.

Returning 45 minutes later, Marta Lukasik tapped her fist on the top of her head -- a diver's signal that means "I'm ok."

On the frozen Lake Kilpisjarvi, just below the tree line at the intersection of the Finnish, Swedish and Norwegian borders, 12 divers were taking a course to learn how to dive in polar regions so they could carry out scientific research.

“Just wow, every little thing you see in the water... Just wow,” said Lukasik, a 41-year-old oceanology PhD student who works as a diving inspector on fish farms in Norway, mesmerized by the experience.

For 10 days, the international group from different professions and backgrounds learned vital skills below the 80 centimetres (30 inches) of ice covering the lake.