Only 1/7 to 1/8 of an iceberg can be seen above water. The rest is hidden below the surface. This does not necessarily mean that the ice underneath the water is six or seven times deeper - it is six or seven times greater in mass.

Icebergs are therefore a great danger to ships, and there have been many collisions over the years.

Therefore the phrase "tip of an iceberg" is used to indicate that one may only be seeing a part of the whole picture.

But although the picture above accurately represents the amount of an iceberg that is hidden underwater, it is not a real picture. The maximum visibility underwater is about 200 feet / 60 meters, so you could never see the underside of a large iceberg in one shot - and where does all the light come from at that depth?

This is a digital composite by Ralph Clevenger, a nature and underwater photographer, who used four separate images: the sky, the background, the top iceberg (shot in Antarctica), and the underwater iceberg (shot above water in Alaska and flipped upside down).