How and why did Odysseus go to Hades?

Answer 1

Odysseus went to the underworld because he wanted to go see a man named Tiresias

After speaking to Circe, Odysseus decided to talk with Teiresias, so he and his men journeyed to the River Acheron in Hades, where they performed sacrifices which allowed them to speak to the dead. Odysseus sacrificed a ram, attracting the dead spirits to the blood. He held them at bay and demanded to speak with Tiresias, who told him how to pass by Helios's cattle and the whirlpool Charybdis. Tiresias also told him that, after his return to Ithaca, he must take a well-made oar and walk inland with it to parts where no-one mixes sea salt with food, until someone asks him why he carries a winnowing fan. At that place, he must fix the oar in the ground and make a sacrifice to appease Poseidon. Tiresias also told Odysseus that, after that was done, he would die an old man, "full of years and peace of mind"; his death would come from the sea and his life ebb away gently. (Some read this as saying that his death would come away from the sea.) While in Hades, Odysseus also met Achilles (who told him that he would rather be a slave on earth than the king of the dead), Agamemnon, and his mother, Anticlea. The soul of Ajax, still sulking about Achilles's armor, refused to speak to Odysseus, despite the latter's pleas of regret. Odysseus also met his comrade, Elpenor, who told him of the manner of his death and begged him to give him an honorable burial.