And in Greenland, scientists suspect the melt waters that drain through holes, or moulins, in the ice cap to the bedrock may have contributed to the speed-up of glaciers in that region, too.

BBC: Under-ice flood speeds up glacier

Many Ukrainians, especially politicians who some joke have more sins than most, step inside ice holes - cut in the shape of a cross - to honour the baptism of Jesus Christ in the Jordan River.

BBC: Pagan holidays in modern Ukraine