Complex sentence: Affluent African Americans from New York and Boston came to Oak Bluffs, and by the 1930s, local black landowners were transforming the town into the country's best-known and most exclusive African American vacation spot.
Split into simpler sentences: Affluent African Americans from New York and Boston came to Oak Bluffs. By the 1930s, local black landowners were transforming the town into the country's best-known and most exclusive African American vacation spot.