Happy Birthday Empire State Building

The Empire State Building, once the tallest building in the world and again the tallest in New York City, is turning 75 years old on Monday.

A yearlong celebration is planned for the building, consisting mainly of monthly light shows, according to Lydia Ruth, spokeswoman for the corporation that runs the building.

Like London's Crystal Palace and the Eiffel Tower in Paris, the Empire State Building represented in its time "what we were capable of," says Carol Willis, an architectural historian and founder-director of lower Manhattan's Skyscraper Museum.

Construction of the Empire State Building was one of the most remarkable feats of the 20th century. It took only 410 days to build -- by 3,400 workers, many of them desperate for work at the height of the Depression. The work force was made up largely of immigrants, along with hundreds of Mohawk Indian iron workers.

The 1,453-foot tower opened on May 1, 1931, with President Herbert Hoover pressing a button in Washington to turn on its lights. Architect William Lamb, the chief designer, messaged former New York Gov. Al Smith from a ship at sea: "One day out and I can still see the building."

Built of steel and aluminum and faced with granite and Indiana limestone, it was for 40 years the world's tallest edifice until surpassed in 1972 by the World Trade Center. It again became the city's tallest after airliners flown by terrorist hijackers destroyed the 110-story twin towers on September 11, 2001. It now ranks ninth in the world, and second in the United States behind Chicago's Sears Tower.

Its 102 floors are topped by a 200-foot tower designed as a mooring mast for dirigibles. The mast was never used because of dangerous updrafts , but it did serve movie "King Kongs" as a perch for swatting fighter planes.