1. On September 14, 1872, Colorado became the first state in the United States to give women the right to vote. This happened 48 years before the 19th Amendment to the U.S. Constitution granted women throughout the country the same right.

2. On September 14, 1858, the first gold miners arrived in Colorado at the confluence of the South Platte River and Cherry Creek in what would later become the city of Denver. This event was the start of the Colorado Gold Rush, which lasted until the early 1860s and brought thousands of people to the area.

3. On September 14, 1901, the Pueblo Chamber of Commerce was established in Pueblo, Colorado. This organization has played a major role in promoting business and economic development in the Pueblo area for over a century.

4. On September 14, 1975, Colorado Governor Richard Lamm officially declared the state's first Energy Day. This annual event is meant to raise awareness about energy conservation and efficiency, and to encourage people to adopt more sustainable energy practices.

5. On September 14, 1988, a massive explosion occurred at the Rocky Flats nuclear weapons plant near Denver, Colorado. The accident released large amounts of radioactive plutonium into the surrounding environment, leading to widespread concern about the safety of the plant and the potential health risks to nearby residents. The incident played a major role in the eventual closure of the plant in 1992.