1. In 1903, the Wyoming Stock Growers Association launched one of the largest manhunts in American history, known as the Johnson County War. The event started on June 15th and lasted for several weeks, resulting in the deaths of many cowboys, ranchers, and law enforcement officials.

2. On June 15, 1928, Amelia Earhart made history by becoming the first woman to fly across the Atlantic Ocean as a passenger. She flew from Newfoundland to Wales with pilot Wilmer Stultz, taking 20 hours and 40 minutes to complete the journey.

3. On June 15, 1939, the iconic Wyoming landmark known as Devils Tower was declared the country's first National Monument by President Franklin D. Roosevelt. The landmark rises over 1,200 feet above the Belle Fourche River and is a popular destination for tourists, hikers, and rock climbers.

4. In 1954, Yellowstone National Park became the world's first national park to have a bear sanctuary. The sanctuary, located in the Tower Fall area of the park, was established on June 15th to provide a safe habitat for the endangered grizzly bear species.

5. On June 15, 1977, a massive tornado outbreak hit the state of Wyoming, causing extensive damage across several counties. The outbreak resulted in over 200 tornadoes over a period of 3 days, with 3 people losing their lives and many more being injured.