1. On May 15, 1930, the Chrysler Building opened in Manhattan, becoming the tallest building in the world at the time. It held the title for only 11 months until the Empire State Building was completed.

2. On May 15, 1862, the United States Bureau of Agriculture was established in New York City. It was the first federal agency created to address agricultural concerns and promote the nation’s farming industry.

3. The first board of trustees meeting for the Metropolitan Museum of Art was held on May 15, 1870. The museum has since grown to become one of the largest and most comprehensive art museums in the world.

4. In 1940, on May 15, the first McDonald's restaurant opened in San Bernardino, California. Although it isn't strictly a New York event, it paved the way for the fast food industry, which has played a significant role in the city's culinary landscape.

5. On May 15, 1918, the United States Army Air Service began a transcontinental flight from Long Island, New York to California. The trip took several weeks and helped lay the foundations for modern commercial air travel.