Ice bubbles in Selbusjø, a lake between Selbu and Klæbu, Norway (© Erlend Haarberg/Alamy)

【February 21 2016】When lake water freezes quickly, it can trap bubbles below the surface. These bubbles, in Selbusjø, a lake in central Norway, were likely formed from methane. Decaying organic matter at the bottom of the lake is eaten by bacteria, which in turn pump out methane gas. If conditions are right, the methane bubbles are captured as the water freezes around them.Explore breathtaking Gallery from the HuluTrip homepage over the past 5 years..