Why does Okonkwo hang himself at the end of the story? What might this gesture symbolize?

Okonkwo is beaten. All that made up his identity has been stripped from him. His son has become a Christian and the white man wields more power than him. He also continues to suffer from the pain of killing his own adoptive son. The gesture symbolizes the end of a people. The Igbo might live on but their former identity, and what Okonkwo saw as glory, was finished.