The Largest Icebergs In History

Big icebergs, which are also called "ice mountains," are huge pieces of freshwater ice that are floating in  open water. They have formed after breaking off continental ice shelves or glaciers.

To be classified as an iceberg, the ice extruding from the water must be at least 15 feet above sea level, be between 100 and 165 feet thick, and must cover an area of at least one-third of a mile, according to the Antarctic Report. Icebergs can have a direct effect on the sea bed, scouring the seafloor where it makes contact.[slideshow:87649]

The biggest icebergs are not the most dangerous ones because they are easily seen on ship radars. The largest ones, which can also be referred to as ice islands, originate from the vast ice shelves surrounding Antarctica. The largest known iceberg was from this region.

About 90 percent of their mass is under water. They come in various shapes – tabular (flat), blocky with steep sides, wedges, dome with rounded top, pinnacle with a pyramid-like top, and dry dock, which is U-shaped near water level. Icebergs are often very unstable because of their random shape combined with different degrees of melting – breakups or rolls can happen suddenly.

Every year about 40,000 medium- to large-sized icebergs break off, or calve, from Greenland glaciers. About 2 percent of them end up near St. John's. One of the best places for seeing the mighty ice lands is Newfoundland and Labrador, a province in Canada. Icebergs are created from pure, fresh water and snow. 

Click here to see the largest icebergs in history

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