Many millennia ago, a snowflake landed at the head of a glacier in the Arctic Circle. In an instant, it turned from a symbol of purity to an agent of death as it triggered the creation of an iceberg - spat from the tongue of the mother glacier and into the ocean. Cameras explore every face of this monstrous glacier, revealing an arterial network of melt-water rivers and frozen masses of rocks and vegetation suspended in the ice, and also the nature of the iceberg. There is a duality to its character. Long before it was a life-taker, it was home to an abundance of arctic wildlife. Passing down through the Arctic Circle and into the North Atlantic, the iceberg was set on an unstoppable collision course that would result in over 1400 deaths. Were warnings heeded? Could the crew of the Titanic have done more to save the passengers - perhaps using the iceberg as a giant lifeboat?