During the 1920s, the Great Migration of African-Americans from the rural South to the urban North continued. The black population of Chicago grew from fewer than 50,000 in 1910 to almost 250,000 by 1930. The 1920s were also the time for new political and cultural developments within the African-American community. Marcus Garvey, who advocated black pride and supported a "back to Africa" movement among American blacks, founded the Universal Negro Improvement Association (UNIA),which espoused black economic cooperation and established black-owned grocery stores, restaurants, and even a steamship company known as the Black Star Line. Although Garvey was arrested and convicted of fraud, the UNIA had more than 80,000 members at its height and was the country's first mass African-American organization. At the same time, New York's preeminent black neighborhood, Harlem, became a magnet for African-American artists, writers, scholars, and musicians. The creative exploration of the black experience by men and women such as Langston Hughes, Claude McKay, Countee Cullen, and Nella Larsen became known as the Harlem Renaissance.