It doesn’t take much to envision what Louis I. Kahn’s memorial to Franklin D. Roosevelt will look like if it is eventually finished. It occupies a triangular, 2.8-acre site at the southern tip of Roosevelt Island in New York City’s East River. Construction crews have already shaped the earth into the exact dimensions and contours that Kahn specified in 1973: a raised lawn, to be flanked by two groves of trees and granite steps, that gently slopes down and culminates in an open-air, granite-walled room overlooking the United Nations. These walls will bear quotes from the president’s powerful Four Freedoms speech.