1. On September 22, 1873, the first passenger train arrived in Denver, Colorado, marking a major milestone in the state's transportation history. The train brought tourists and settlers from the east, paving the way for further development of the state.

2. In 1908, the Colorado School of Mines football team played their first game against the Denver Athletic Club on September 22. The game ended in a 0-0 tie, but it was the start of a long and storied tradition of football at the school.

3. September 22, 1930, saw the dedication of the Museum of Natural History in Denver. Today, the museum is known as the Denver Museum of Nature & Science and is one of the largest natural history museums in the Western United States.

4. In 1983, the United States Air Force Academy in Colorado Springs welcomed its first female cadets on September 22. This event marked a major milestone in the history of the academy and paved the way for greater gender equality in the military.

5. On September 22, 2011, the Colorado Rockies defeated the Houston Astros 6-3 in the final game of the regular season, securing a spot in the playoffs. The win was especially significant as it marked the first time in the team's history that they made the postseason in back-to-back years.