Hindus believe that Vishnu has many important avatars. The Vamana avatar was the fifth avatar. In this avatar, Vishnu was in the form of a human.Vamana avatar is basically in the form of a bramhin(a caste in hinduism which is responsible for ancient spiritual, cultural, educational activitiesand the highest in the Varnas) was taken for a demon king 'Bali'. Lord Vishnu in this avatar asked Bali to offer him 'three feet land' as a form of offering a king offered to a brahmin as a goodwill during ancient times in hindu culture. The story goes when king Bali captured the Adobe of hindu demigods and caused them a fierce battle. 'Aditi' - the mother figure of demigods in hinduism prayed to Lord Vishnu and pleased by her prayers, Lord Vishnu appeared and assured her a boon. In a thought of revenge , she wished that may Bali loose his whole wealth and power." 