The Underworld and then through the Harpies and sea monsters; Scylla and Charybdis.
The Charybdis is a giant whirlpool that lives under an enormous fig tree. It tried to suck in Odysseus's ship.
He lose them to Scylla when they pass through the straits of Scylla and Charybdis.
Odysseus chooses to pass by Scylla because, Scylla will only kill 6 men, one for each head. Charybdis will sink the ship, killing everyone. Circe has also advised Odysseus to do choose Scylla. Further, Charybdis is a visible danger, and Odysseus uses Charybdis to encourage his men to pass by quickly. Finally, passing by Scylla and Charybdis is given as the only way for Odysseus to get home from where he is.
He needed to sail pass this strait to get home to Ithaca.
He plugged the sirens ears and avoided the Charybdis
Odysseus goes through the Sirens by putting beeswax in their ears. Odysseus is tied to the mast while the Sirens are surrounding them and is begging for his soilders to untie him but they don't. He goes through Scylla by just going past it, letting 6 of his men get eaten by Scylla. And he sailed closer to Scylla to get past Charybdis.
Odysseus donned his armor and readied his spear to attempt to fight of Scylla. He then ordered his men to hug the rocks, where Scylla was, as to avoid Charybdis. He was unable to prevent the capture of his 6 men.
Circe warns Odysseus of the dangers in store for him and his crew on their journey home. These dangers include the Sirens, Rovers, Scylla and Charybdis, and Helio if his cattle are slaughtered.
Odysseus chooses to go on Scylla's side of the strait because he believes facing the danger of Scylla is a less risky option than facing Charybdis, the whirlpool monster. He hopes to minimize casualties by sacrificing only a few men to Scylla, rather than risking losing the entire ship to Charybdis.
Circe
so that he can die