1. In 1867, the United States purchased Alaska from Russia for $7.2 million. Although this event occurred in Washington D.C., it had a significant impact on the economy of New York City, which became a crucial port for the transit of goods and people between the United States and Alaska.

2. On March 30, 1870, the Fifteenth Amendment to the United States Constitution was ratified, guaranteeing African American men the right to vote. This landmark event led to the formation of new political parties and the strengthening of the civil rights movement in New York and across the country.

3. In 1909, the Queensboro Bridge opened to traffic, connecting Manhattan and Queens for the first time by a permanent roadway. The bridge, also known as the 59th Street Bridge, became a symbol of the modernization of New York City, and was celebrated in popular culture, including in the song "Feelin' Groovy" by Simon and Garfunkel.

4. On March 30, 1939, the New York Yankees became the first major league baseball team to wear numbers on their uniforms, as they played an exhibition game against the Boston Red Sox at Yankee Stadium. The tradition of uniform numbers caught on quickly, and soon became standard practice throughout professional sports.

5. In 1981, John Hinckley Jr. attempted to assassinate President Ronald Reagan outside the Hilton Hotel in Washington D.C. One of the victims of the shooting was James Brady, the White House Press Secretary, who was left partially paralyzed. The incident led to the passage of the Brady Handgun Violence Prevention Act in 1993, which imposed background checks and waiting periods for the purchase of firearms.