Complex sentence: In 1957, he launched a campaign known as the Great Leap Forward that aimed to rapidly transform China's economy from an agrarian economy to an industrial one, which led to a widespread famine whose death toll is estimated at between 18 and 45 million.
Split into simpler sentences: In 1957, he launched the Great Leap Forward campaign that aimed to rapidly transform China's economy from an agrarian economy to an industrial one. The campaign led to a widespread famine, whose death toll is estimated at between 18 and 45 million.