Jacob Riis was one of the very few men who photographed the slums of New York at the turn of the century, when as many as 300,000 people per square mile were crowded into the tenements of New York's Lower East Side. The filth and degradation made the area a hell for the immigrants forced to live there. Riis was one of those immigrants, and, after years of abject poverty, when he became a policeā¦