Episode Seven of the New York: A Documentary. In the aftermath of World War II, southern African-Americans moved north and Puerto Rican immigrants poured into the city, a trend which would continue for the next thirty years. Robert Moses waged a campaign of urban renewal, including adding highways to the city, hastening white flight to the suburbs. The destruction of the old Penn Station in 1963 and the protests against Moses's plans for the Lower Manhattan Expressway led to the creation of the New York City Landmarks Preservation Commission, ensuring the survival of New York's most architecturally important buildings and neighborhoods. Social and financial crises in the 1960s and 1970s took a toll on the city, but New York's revival since the 1970s has been enduring.