At the bottom of the Caspian Sea the unknown fortress has been found out

Investigation of shelf of Absheron peninsula using space photographs allowed scientists to find an extraordinary structure on the bottom of Caspian sea, near the eastern boundaries of Absheron peninsula i.e. Shikhov bay bar and the shape of this structure reminded the ruins of an ancient fortress. Authors temporarily titled this structure as «Zyrinskaya fortress». Special filters providing for viewing of the space photograph in various spectral ranges have been used in order to improve visual capacity of the obtained picture. Authors managed to some extent to get common understanding of possible spatial design of a number of components of the ancient fortress using methods of three-dimensional graphics. Implementation of special software allowed for identification of precise parameters of Zyrinskaya fortress. The length of fortress equals to 316 meters, and the width of fortress equals to 140 meters. Perimeter of exterior walls of the fortress amounts to 823 meters. The area of interior part of the fortress equals to 38960 square meters. Diameter of semicircular interior structures equals to 21-25 meters. Thickness of external walls is equal 2-2,5 meters.