Shreve, Laub, and Harmon. The "tallest building" when it was finished in April 1931, it lost
Shreve, Laub, and Harmon. The "tallest building" when it was finished in April 1931, it lost
its title in the 1970's to both Chicago's Sear's Tower and the World Trade Center in New
its title in the 1970's to both Chicago's Sear's Tower and the World Trade Center in New
−
York. It remains, however, New York city's most widely recognized architectural symbol. [http://www.nps.gov/nhl/designations/samples/ny/empire.pdf]
+
York. It remains, however, New York city's most widely recognized architectural symbol. <ref> [http://www.nps.gov/nhl/designations/samples/ny/empire.pdf The Empire State Building.] </ref>