1. On March 15, 1913, the first ambulance service in New York City began operating out of Bellevue Hospital. The service was revolutionary in that it provided rapid response and transportation for emergency medical situations, significantly improving patient outcomes.

2. In 1962, the iconic Four Seasons Restaurant in New York City opened its doors for the first time on March 15th. The restaurant was revered for its modern cuisine and elegant decor, attracting a celebrity clientele that included Frank Sinatra, Jackie Kennedy, and Salvador Dali.

3. The first recorded St. Patrick's Day parade in New York City took place on March 15, 1762. The parade was organized by Irish soldiers serving in the British army, and has since grown to become one of the largest St. Patrick's Day celebrations in the world.

4. March 15, 1956 marked the opening of the first container ship service between New York City and Puerto Rico. The service, operated by Sea-Land Corporation, revolutionized the shipping industry by increasing efficiency and reducing costs.

5. On March 15, 1820, Maine was admitted as the 23rd state in the union. The state was originally part of Massachusetts, but was separated and granted statehood in a compromise that also admitted Missouri as a slave state. Maine's admission as a free state helped to maintain the balance of free and slave states in the union.