Goddess Durga killing the demon Mahishasura. Durga is the Goddess of power and strength.Goddess Durga is incarnation of Mother Goddess a unified symbol of all divine forces. The Sanskrit word Durga means a fort, or a place that is protected and thus difficult to reach.  The Hindu Mother Goddess Durga manifested when evil forces threatened the very existence of the Gods. She is a spectacular personification of cosmic energy.  Mahishasura the king of Demons, was once granted a boon by Lord Shiva. pleased with the devotion of Mahishasura;Lord Shiva blessed him with a boon that no man or God would be able to kill him. The gods, scared and powerless to counter this tyranny, requested Lord Brahma, Lord Vishnu and Lord Shiva to annihilate Mahishashura. Shiva opened his third eye and concentrated the energy coming out of it to form a woman. All the Gods who were present there contributed their share of energy to this  Goddess and thus Devi Durga was born. Riding a lion, she attacked Mahishasura and beheaded him. Mahishasura took the form of the evil buffalo demon in the battle but he was killed by the unconquerable Goddess.