Abstract: A piston-chamber hydro-gravity engine capable of converting the stagnant volume of the liquid matter of sea, lake, pond or artificially made hydro container, to a moving volume of liquid matter that flows back upon itself and in meanwhile exploits this motion as a working agent to produce mechanical kinetic power, capable of being used for mechanical production of kinetic work for hydro-electricity generation, or to be used multi-purposely for other energy needs that demand mechanical kinetic force sufficient to solve energy production problems worldwide forever beneficial to the economy and, friendly to the environment, consisting of particular accessories of mechanisms embodied in a single system of mutual successive co-operation by exploiting gravity, that is the hydro-container (7), capable of creating the means of exploiting the gravity-hydro-static tension of squashing compression exist within the volume of liquid matter of the sea, lake, pond or artificially made containers, the cylinder-chamber (15) a