Muammar Gaddafi was killed on October 20, 2011. Fighters overran his hometown of Sirte, the last city loyal to him, and found him hiding in a drain pipe after his convoy was hit from the air. He had ruled Libya for 42 years.
The revolution had begun in February, part of the Arab Spring that swept the region. Protests turned into an armed uprising, and NATO aircraft enforced a no-fly zone that blunted Gaddafi's counterattacks. Tripoli fell in August. He fled east toward Sirte.
He was dragged from the pipe and beaten, and the circumstances of his death were never cleanly established. Video of the scene spread quickly, and the fighters who had taken him appeared to have killed him after capture. The new authorities promised an investigation that never really came.
The man was gone, and so was the state he had held together. Gaddafi had ruled through a mixture of oil wealth, fear, and a system he called the Jamahiriya, which concentrated power in his own hands. With him removed, there was no agreed successor and no institutions to fall back on.
Libya fell into war. The country that had revolted against one dictator split among militias and factions, and a decade later it was still divided between rival governments. The killing of Gaddafi ended one era and started a much harder one.