Christian R. Greco found the earliest known photographs of his family by accident. In the wake of President Trump’s decision to walk back some protections for young undocumented immigrants, the historian and legal activist couldn’t help but think about his own family’s immigration experience and his father’s journey to New York from Italy in October of 1950.

Inspired to look for images from Ellis Island from that period, he stumbled upon a LIFE.com gallery that contained several Alfred Eisenstaedt photos that were never published in the magazine.