A few years after the Titanic sank there was an ice patrol. Ever since the ice patrol was on duty, a ship has never sunk.

Most of an iceberg is under water. Icebergs that are flat on top are called flat-tops.

The army dropped bombs on icebergs and used a chemical half as hot as the sun. The bombs broker off small pieces of the iceberg and the chemicals only made a hole a few inches deep in the iceberg.

Scientists have not yet found a way to destroy an iceberg.