Vaman Avatar was the fifth Avatar of Vishnu.
The story of Vaman Bhagvaan ( Bhagvaan means god) is some how related to the story of Samundar Manthan (click here to know about the story). As Indra and all other devtaas lost their powers the Daanavas took the advantage of this opportunity . The King Bali , the king of Daanavas attacked them and they conquered the whole universe. Universe is also referred as three loks, these are loks Prithvi lok(means world) ,Aakash lok or Swarg lok means (heaven) and paatal lok.
King Bali was the grand son of Prahlada (click here to know who was Prahlada). he was also called Daanveer Rajja Bali. Daanveer means a person who can give any thing he is asked for, in donation and Rajja means the king.
Vaman was a Dwarf Bhramin, he carries a kamandal and a wooden umbrella . Vamana went to Rajja Bali and asked him for three steps of land for Tapasya (meditation). the King agreed to give him land and asked him to measure the land where ever he wants. Vamana smiled at his promise and he enlarged his body to such a dimensions that he measured the Akasha (Sky) in one foot and the Prithvi(earth) in second foot and for the Third foot the king Bali asked him to step over his head. Vamana was so pleased with his Daanveer nature that he steped over his head and Gave him the kingdom of Paatal lok. the King was then called MahaBali, Maha means great. The holi festival of Onam is celebrated in the remembrance of this incident.