Ellis Island was the main portal of entry to the United States for immigrants from Europe in the early part of the 20th century. Millions of people came through there...my grandparents included. It fell into terrible disrepair but underwent a massive restoration and reopened in 1990.   Here is the National Park Service's website, that includes a link to the history of the site and info about the current museum exhibits. Search for "ellis island" on Google for more information, including some commercial sites that I haven't examined too closely. Here are some fascinating stereoscopic photos of Ellis Island when it was active.

Aloha,
Mark