Bordered by Back Bay, Roxbury, and Chinatown, the South End was once a tidal marsh with a narrow strip of land connecting the Shawmut Peninsula (today's Downtown Boston) to the neighboring mainland town of Roxbury. Known as the "Boston Neck," that strip of land was the foundation upon which the neighborhood was created in the 19th century. Boston's South End recounts the history of the neighborhood from its inception as a wealthy residential district to a vibrant immigrant community in the early 20th century.