1. 1919: Grand Canyon National Park was established in Arizona, United States.

2. 1952: British Prime Minister Winston Churchill announced that the United Kingdom had developed its own atomic bomb.

3. 1993: World Trade Center bombing: A truck bomb exploded in the parking garage of the World Trade Center in New York City, killing six people and injuring over a thousand.

4. 2012: Trayvon Martin, a young African American, was fatally shot by George Zimmerman in Florida, sparking national debates about racial profiling and self-defense laws.

5. 2021: NASA’s Perseverance rover successfully landed on Mars, beginning its mission to search for signs of past life and collect samples of rock and regolith.