Which floods were the deadliest in history and claimed millions?

The world's deadliest floods have claimed millions of lives, with China's 1931 floods remaining the worst recorded disaster. Other major tragedies include the 1887 and 1938 Yellow River floods, the 1970 Bhola cyclone, the Kaifeng flood and the Banqiao Dam failure. Historical death tolls vary because many estimates include later deaths from famine, disease and displacement.