1. In 1870, Colorado became the 38th state in the United States of America. The state joined the Union in the aftermath of the American Civil War.

2. In 1932, the Indian Peaks Wilderness Area was established near the center of the state. The area contains alpine lakes and peaks and is popular among hikers and trout fishermen.

3. In 1959, the United States Air Force Academy was founded near Colorado Springs. The academy trains officers for the Air Force and is located on 18,000 acres of land.

4. In 1993, the Aspen Center for Environmental Studies was established in Aspen, Colorado. The center is dedicated to educating the public about the environment and is home to several nature preserves and hiking trails.

5. In 2014, Colorado became the first state to legalize recreational marijuana. The move was controversial, but many advocates argued that it would help to reduce crime and generate revenue for the state. Today, Colorado is one of several U.S. states that have legalized cannabis use.