April 30, 1939 — The New York World’s Fair opens

Dedicated to the promise of tomorrow, the New York City World’s Fair opened on Sunday, April 30, 1939. A crowd of more than two hundred thousand people braved the queues and the heat to investigate the attractions of the Fair. Many of the attractions were still not completed, but no one much cared. President Franklin D. Roosevelt made the opening address, which many of the crowd watched on the two hundred television sets – television being a new invention at the time.

Best known for the iconic Trylon and Perisphere built especially for it, the World’s Fair ran from April to October in 1939 and 1940, closing its doors for good on October 27, 1940. It was the largest World’s Fair ever – even the 1964 World’s Fair, which was held on the same site, was not as large.

January 8, 1815 — The Battle of New Orleans takes place

In the annals of military pointlessness, few battles are quite as ridiculous as the Battle of New Orleans. It was fought 16 days after the official end of the War of 1812, of which it was a part, due to the fact that the peace treaty was signed in Europe, and the news took two months to reach America.

The Battle of New Orleans was important to later American history, though. It ended the war with a decisive American victory (in a war where neither side had managed to seize the advantage over the other), and it brought to prominence a commander named Andrew Jackson, who would later become the seventh President of the USA.

Battle of New Orleans, Jean Hyacinthe de Laclotte.jpg
By Painting by Jean Hyacinthe de Laclotte (1766 – 1829), a member of the Louisiana Militia who participated in the battle; painted by him after the victory based on his sketches made at the scene. – New Orleans Museum of Art, Public Domain, Link

As mentioned in:

I Ain’t Marching Anymore — Phil Ochs
Lydia the Tattooed Lady — Groucho Marx
The Battle of New Orleans — Johnny Horton