The event that marked the beginning of the Great Migration in the United States was the mass relocation of African Americans from the rural South to the urban North, commencing around 1916 and continuing into the 1970s. This migration was driven by several factors, including the search for better job opportunities, escape from oppressive Jim Crow laws, and the desire for a better quality of life. World War I played a crucial role as industrial jobs became more available in Northern cities, providing African Americans with paths to economic advancement. This migration significantly transformed the cultural, social, and demographic landscape of America, leading to changes in demographics and the development of vibrant African American communities in Northern cities.