What artifact did the Greeks allegedly use to win the Trojan War?

The Trojan War is a legendary conflict between the early Greeks and the people of Troy in western Anatolia, dated by later Greek authors to the 12th or 13th century BCE. The war stirred the imagination of the ancient Greeks more than any other event in their history and was celebrated in the Iliad and the Odyssey of Homer. The ensuing war lasted 10 years, finally ending when the Greeks pretended to withdraw, leaving behind them a wooden horse of large proportions with a raiding party concealed inside. When the Trojans brought the horse into their city, the hidden Greeks opened the gates to their comrades, who then sacked Troy.

Source: Encyclopedia Britannica