Iceberg
This photo was sent by the administrator of the Global Marine Drilling petroliferous platform, that is located in St.Johns, Newfoundland.
They are in charge of changing the course of icebergs, by towing, to avoid them hitting the platforms.
In this case, the sea was calm, the crystalline water and the sun affected the iceberg almost directly, so that a diver could take this wonderful photo.
They considered the weight of this iceberg to be about 300 million tons. Things like this make us understand why a photo is worth than thousand words…