In what ways is Dante's trip to hell an allegory?

Dante's Inferno is an ,
which means it is a work that operates on both a literal and a symbolic level at once.

Take the firstof Inferno, for example. Dante wakes to find himself
in the "dark wood of error." His character is literally in a forest that has a path
(the "straight path") and a hill in the distance. On the symbolic level, the forest
represents a life of sin, while the path represents a path of redemption that takes the contrite
and forgiven sinner to heaven (the hill). In this canto, Dante is also ambushed by three beasts,
which represent temptations like greed, anger, and lust. He finds that he cannot continue on the
path while those beasts are in his way; this symbolizes how Dante does not feel able to overcome
his temptations yet. Luckily for him, Virgil appears and offers to take Dante on a journey
through all of the circles of hell as an alternate way to purgatory and then to
heaven.

During the journey, Dante witnesses the symbolic punishments of a
variety of sinners. For example, the sinners who are in the second circle, for "the
carnal," are swept up in a whirlwind for all eternity, like they were swept up in their
emotions during their lives. Each circle of hell punishes the sinners therein in appropriate
ways that reflect the sins for which they are being eternally damned. At the end of
Inferno, Dante climbs onto Virgil's back and together they literally
surmount Satan himself. The symbolism here is clear: Dante must overcome the most evil being of
all to move away from a life of sin.