The "adventure that took Odysseus ten years" refers to his return journey to Ithaca after the Trojan War, immortalized in Homer's Odyssey. While the war itself lasted ten years, his homeward voyage added another decade of trials, making twenty years total absence.
After sacking Troy, Odysseus angered Poseidon, god of the sea, by blinding his son, the Cyclops Polyphemus. The sea god's wrath manifested as storms, shipwrecks, and diversions that transformed a weeks-long voyage into a decade-long odyssey.
Arriving disguised as a beggar, Odysseus finds his palace overrun by 108 suitors courting his wife Penelope. With his son Telemachus and a few loyal servants, he slays them in a climactic bow contest and battle, reclaiming his kingdom and identity.
The Odyssey explores nostos (homecoming), xenia (guest-friendship), metis (cunning intelligence), and the human struggle against divine will and natural forces. It remains a foundational Western text on resilience, identity, and the meaning of home.