Ganesha is the son of Shiva and Parvati. He is considered the god of wisdom.
The devotees worship him at the start of any new undertaking for its success.
The god is special in that he carries the head of an elephant.
Ganas were attendants of Shiva and Parvati. Once Parvati, alone at home and going for a bath, asked one of the Ganas to stand as a guard and not allow anyone in.
The Gana made an exception of Shiva, which made Parvati angry. Shiva told her to have her own Gana.
She made one out of the saffron paste on her body, called him her son and posted him as a guard.
This Gana boy refused entry to Shiva, fought Shiva`s Ganas and even the gods that came to assist them.
Finally, Shiva beheaded him, only to find Parvati extremely angry for Shiva had harmed her son.
Shiva revived the Gana with the head of the first creature found, which was an elephant.