Complex sentence: In the first--and deadliest--attacks, 242 planes hit Darwin on the morning of 19 February 1942, killing at least 243 people, causing immense damage, making hundreds of people homeless and causing the abandonment of Darwin as a major naval base.
Split into simpler sentences: In the first and deadliest attack, 242 aircraft hit Darwin on the morning of 19 February 1942. Killing at least 243 people and causing immense damage, the attack made hundreds of people homeless and resulted in the abandonment of Darwin as a major naval base.