Odysseus comes up with the idea to build the wooden horse as a way to enter the city and sabotage them (the Trojans). They made it look as if it was a gift and a symbol of their victory. And the trojans had no idea The greeks were in side and were ready at any moment to attack
The city of Troy is destroyed and the trojan war is now over. Hecuba was chosen as the last sacrifice with her blood as expiation to Achilles' death. This was the peacemaker of their 7-10 year war.