Icebergs are formed from glaciers, which are massive slabs of ice comprised of layers upon layers of ice that have built up over thousands of years. Depending on the temperature of the water, once calved, an iceberg can live for up to six years. Throughout the iceberg's existence, waves crash up against it, forcing it against land and other bergs. Heat/warmth cycles help develop the complex shape of the iceberg, sometimes forming huge holes. Some icebergs melt away and others violently collapse under their own weight.
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