America's self-image has long been that of a melting pot -- a refuge for the "huddled masses yearning to breathe free" and "a nation built by immigrants." The country's history is also replete with examples of shutting the door on arrivals from places like China, Eastern and Southern Europe, and more recently, from predominantly Muslim nations and Central America. In other words, America's relationship with immigration is complicated.

Pictured: An Italian family looking for lost baggage, Ellis Island, c. 1904-1926
Lewis Hines/The New York Public Library