Complex sentence: Against all odds, the rats held Tobruk tight until December of 1941, when they were evacuated by the British Navy after holding Tobruk for two hundred and fifty days, a little over eight months.
Split into simpler sentences: Against all odds, the rats held Tobruk tight until December of 1941, when they were evacuated by the British Navy. The Rats of Tobruk held their town for two hundred and fifty days, a little over eight months.