1. Idaho Day: On July 12, 1890, President Benjamin Harrison signed a bill making Idaho the 43rd state in the United States. To celebrate the event, Idahoans celebrate July 12 as Idaho Day.

2. Atomic City: In 1949, the first atomic bomb was successfully tested in the Idaho desert by the US government. The explosion earned the area the name "Atomic City" and prompted the creation of a research facility known today as the Idaho National Laboratory.

3. Teton Dam Disaster: On July 12, 1976, the Teton Dam in eastern Idaho failed, resulting in a catastrophic flood that killed 11 people and caused $1 billion in damages. The disaster was one of the worst in US history and prompted major changes in dam construction and management nationwide.

4. Ernest Hemingway: The famous author Ernest Hemingway died on July 12, 1961, in Ketchum, Idaho, where he had a home. Hemingway had visited Idaho frequently and even wrote parts of his novel "For Whom the Bell Tolls" while staying there.

5. Lewis and Clark Expedition: In 1806, the Lewis and Clark Expedition, which explored the western portion of the United States, crossed into what is now Idaho on July 12. The group traveled along the Clearwater River and crossed the mountains near Lolo Pass, making it one of the most challenging parts of their journey.