Complex sentence: The belly gunner of an American B-17F bomber fell 20,000 feet onto the glass roof of the train station, even though his parachute had been destroyed by German flak while still on his plane.
Split into simpler sentences: The belly gunner of a B-17F fell 20,000 feet onto the glass roof of the train station. Even though his parachute was destroyed by German flak while still on his plane.