Found 30 metres underground at a coal mine, they're dubbed 'Jurassic pearls' or the marbles of a Siberian colossus.
Giant natural balls in the Franz Josef archipelago that leave scientists flummoxed.
'If we die, I love you,' says one bather struck by bullet-like giant hail stones.
When Vadim Kolpakov went on an expedition to the north of Irkutsk region, he had no inkling of the sensational discovery he was about to make.