1887 Yellow River Flood, China

The 1887 Yellow River Flood killed between 900,000 and 2 million people — up to 15 times more than the 2011 Tōhoku earthquake — submerging 11 cities and hundreds of villages under up to 20 feet of water. Called "China's Sorrow" for its catastrophic flooding history, the Yellow River has changed course 26 times in recorded history, with the 1887 shift being the deadliest single change. The disaster was partly caused by decades of deforestation and poor levee maintenance, leading to a 40% increase in land erosion rates prior to the event, leaving millions vulnerable to the inevitable breach.