The Partition of India (1947)

The British decision to partition India along religious lines created India and Pakistan but triggered the largest mass migration in human history — 15 million people displaced and up to 2 million killed in sectarian violence. The hastily drawn Radcliffe Line split communities, families, and resources, and the resulting India-Pakistan rivalry has produced four wars, a nuclear arms race, and the unresolved Kashmir conflict that persists to this day.