The Great Famine, or the Potato Famine, began when a late blight (Phytophthora infestans) destroyed the potato crop, the primary food source for one-third of the Irish population. The crisis was exacerbated by the British government's adherence to 'laissez-faire' economics, which prevented effective aid and allowed food exports to continue while people starved. Approximately one million people died of hunger and disease, and another million emigrated, mostly to the United States. This event halved Ireland's population in a decade and fostered a deep, lasting resentment against British rule, fueling the movement for Irish independence. It remains a foundational and tragic event in Irish history and a global case study in the failure of government response during a humanitarian crisis.