Samsāra, the Sanskrit and Pali term for "continuous motion" or "continuous flow" refers in Buddhism to the concept of birth, old age, decrepitude, and death, in which all beings in the universe participate and from which one can only escape through enlightenment.
The wheel of Samsara encompasses six different paths, defined on the basis of karma. However, no matter how blessed an existence is achieved, suffering is still inevitable: even the most well-born beings are still subject to the evils of the world, and to rebirth. Only enlightenment breaks the cycle.
Deva: first divine path, sometimes referred to as god-like existences, Devas are the most sublime stage of Samsara, reserved for those with positive karma. Even with divine powers and knowledge, they are still subject to reincarnation and the evils of human beings, such as pride, lust, anger, and so on. One of the two divine paths, representing the positive side.
Asura: the second divine path, representing the opposite extreme of a Deva, the bad side. People who were jealous, angry and bloodthirsty tend to be reborn as Asuras, the demonic path. Like the Devas, they have extraordinary abilities and are also subject to karma and reincarnation.
Manusya: the human beings. It is based on pride, passion, desire and doubt, and is considered the most favorable path to reach nirvana, since they can obtain the necessary information for this, without the strong carnal desires and obsessions of the higher paths interfering in this process.
Animal: It is believed that there are people who are reborn as animals, due to the state of ignorance, dominance of instinct, survival of the fittest, and servitude to humans that these people were in in their previous lives.
Black: the path of hungry ghosts. Path based on strong possessiveness and desire in previous lives, they are humanoid creatures, pale and thin, precisely because they are always hungry and thirsty, but are unable to satiate their perpetual hunger and thirst.
Naraca: the closest thing to Hell in Buddhism. All those who are sent to the Naraca path only stay there until they balance their karma, thus being able to be reborn (which shows that Naraca does not keep anyone eternally imprisoned). There are Eight Cold Naracas and Eight Hot Naracas, and each one is a stage for balancing karma.