Since the 17th century, the legend of the Flying Dutchman, a ghost ship supposed to float above the waves and sign of a curse, has been told. The optical illusion which is at the origin of this legend is called fata morgana. This name comes from the Morgan fairy of the Arthurian legends, because the first crusaders to have observed this phenomenon thought that the Morgan fairy had the power to make palaces float above the sea and to act on the wind.The most typical cases of fata morgana occur in the middle of the ocean, due to the conjunction of a type of mirage with certain temperature zones, but they are also sometimes seen on land. It requires a cold air mass close to a surface such as the ground or the ocean, and a large mass of warm air above it. This configuration distorts the light rays that pass through and with them the image of objects that appear to be displaced and distorted. The farther you are from the mirage, the larger the ghost image appears.Fata morganas are more common in certain places around the world where the right conditions are always present for it to be created. The Antarctic, the Great Lakes region of the United States, the Gulf of Bothnia, the Baltic Sea, the Strait of Messina, the Californian coast among other examples.
