Saṃsāra (Sanskrit, Pali; also samsara) in Buddhism is the beginning-less cycle of repeated birth, mundane existence and dying again. Samsara is considered to be dukkha, unsatisfactory and painful, perpetuated by desire and avidya (ignorance), and the resulting karma. Rebirths occur in six realms of existence, namely three good realms (heavenly, demi-god, human) and three evil realms (animal, ghosts, hellish). Samsara ends if a person attains nirvana, the "blowing out" of the desires and the gaining of true insight into impermanence and non-self reality.