Aum Jayanti Mangalaa Kaalee Bhadra Kalee Kapalinee
Durgaa Kshamaa Shivaa Dhatree Swaaha Swadhaa Namoo Stute
The Goddess Durga (meaning difficult to reach) has many names. Amba, Paarvati, Kaali, Gauri are some of the more well known names. She is the incarnation of Paarvati, the consort of Lord Shiva. She incarnated in this form to kill the demon Mahishasura. Hence She is also called Mahishasura Mardini. The city of Mysore is named after Her. The legend is narrated in the famous Deevi Mahatmyam.
Sri Durga has several arms. She is depicted as having eight arms holding a different type of weapon in each arm but She is also known to have eighteen arms. She is also depicted in the terrible Kaali form in which She is shown standing on a corpse with out-stretched tongue and unfurled hair. She is the personified Energy of the Lord Naaraayana Himself. Hence She is called Shakti and Her worshippers are called Shaakteeyas.
Durga is worshipped by women for long and happy marital life. She is worshipped during the festival of Navaraatri associated with Dasera. The festival occurs on the eigth day (Ashtami) of the fortnight. Hence the day is called Durgaashtami. She is especially popular in Bengal, perhaps due to the influence of Raama Krishna Parama Hamsa who worshipped Kaali as Mother.