Dante's universe is divided into three parts: Inferno (hell), Purgatorio (purgatory), and Paraiso (heaven).
Inferno
Inferno is an abyss with the shape of an inverted cone. It is divided into 9 circles, each circle corresponds to a different sin, where the condemned are subjected to punishment, according to the gravity of the sins committed in life.
The circles, from the first to the last, are: Limbo, contains the unbaptized and virtuous pagans; Lust; Gluttony; Greed; Wrath; Heresy; Violence; Fraud; and Treachery, in the vertices of the cone, where lies the Palace of Lucifer and in it Lucifer himself who is biting Judas with his sharp fangs.
Purgatorio
It is a mountain made with the earth taken from the abyss of hell. The mountain is divided in the Ante-purgatory at the base and 7 cornices, where souls purge their sins before entering to Heaven. In the first cornice, at the base of the mountain, are those with the most serious faults, and at the top those less guilty. Sins here are more based on motives, instead of actions as it is the case in Inferno.
The order is (from bottom to top): Ante-purgatory, where lie the excommunicate and late repentant; the proud; the envious; the wrathful; the slothful; the covetous; the gluttonous; and the lustful.
Paraiso
Paraiso consists in a series of nine concentric spheres in whose center lies the Earth, seven of them corresponding to a different celestial body, the eighth to the fix stars and the last one to the Primum Mobile (God).
The order of the spheres is like follows: the Moon, corresponding to the virtuous that lacked consistency and Fortitude; Mercury, reserved for those who did good only earthly ambition and deficient in Justice; Venus, for the lovers but deficient in Temperance; the Sun, for the wise and greatest example of Prudence; Mars, for the warriors of faith, greatest examples of Fortitude; Jupiter for the right rulers, who embody Justice; Saturn, for the Contemplatives, greatest examples of Temperance; Fixed stars, for the Saints; Primum Mobile, the 'first moved' sphere, realm of angels and moved by God, who is beyond physical existence in the Empyrean.