2. Treaty of Lateran: Benito Mussolini and Pope Pius XI signed the Lateran Treaty, establishing Vatican City as an independent city-state and resolving a decades-long conflict between Italy and the Catholic Church.
3. Young Plan: The Young Plan, an agreement restructuring Germany's World War I reparations, was signed by Germany and allied countries to reduce Germany's debt burden and promote economic recovery.
4. First Academy Awards: The first Academy Awards ceremony was held in Los Angeles, honoring the best films of the previous year.
5. Kellogg-Briand Pact: The Kellogg-Briand Pact was signed by dozens of countries, renouncing war as an instrument of national policy and promoting peaceful resolution of conflicts.
6. Women's Suffrage: In the United States, the women's suffrage movement achieved a major victory as the Nineteenth Amendment to the U.S. Constitution was ratified, granting women the right to vote.
7. Discovery of Pluto: American astronomer Clyde Tombaugh discovered Pluto, the ninth and farthest planet from the Sun at that time. Pluto's status has since been reclassified as a dwarf planet.
8. Gandhi's Salt March: In India, Mahatma Gandhi launched the Salt March, also known as the Dandi March, to challenge the British salt monopoly as part of the Indian independence movement.
9. The Great Gatsby: F. Scott Fitzgerald's novel "The Great Gatsby," considered one of the greatest works of American literature, was published.
10. Universal Studios: Universal Studios, one of the major Hollywood film studios, was incorporated, giving rise to the Golden Age of Hollywood.