Ellis Island earned landmark status through three intertwined legacies:
12 million processed (1892–1954); peak 1M+/year (1905–14). The "Golden Door" where European masses entered. Medical rigor (trachoma, favus, mental exams) became national standard.
Eastern/Southern European immigrants (Italians, Jews, Poles, Slavs) reshaped U.S. cities, labor, politics, culture. Their descendants are >100M Americans today. Ellis Island symbolizes hope, opportunity, diversity—and the contested politics of belonging.
It's not just a building; it's a national origin story.