On what holiday did construction of the Empire State Building begin?

The Empire State Building is a 102-story skyscraper located on Fifth Avenue between West 33rd and 34th Streets in Midtown, Manhattan, New York City. It has a roof height of 1,250 feet (381 m), and with its antenna included, it stands a total of 1,454 feet (443.2 m) tall. Its name is derived from the nickname for New York, the Empire State. It stood as the world's tallest building for nearly 40 years, from its completion in early 1931 until the topping out of the original World Trade Center's North Tower in late 1970. Following the September 11 attacks in 2001, the Empire State Building was again the tallest building in New York, until One World Trade Center reached a greater height in April 2012. The Empire State Building is currently the fifth-tallest completed skyscraper in the United States and the 35th-tallest in the world. It is also the fifth-tallest freestanding structure in the Americas. When measured by pinnacle height, it is the fourth-tallest building in the United States.

Excavation of the site began on January 22, 1930, and construction on the building itself started on March 17—St. Patrick's Day—per Al Smith's influence as Empire State, Inc. president. The project involved 3,400 workers, mostly immigrants from Europe, along with hundreds of Mohawk iron workers, many from the Kahnawake reserve near Montreal. According to official accounts, five workers died during the construction. Governor Smith's grandchildren cut the ribbon on May 1, 1931.