1. On April 6, 1874, the town of Aspen was incorporated. Located in the heart of the Rocky Mountains, Aspen became known for its silver mining and later on, as a popular ski destination.

2. The first legal sale of recreational marijuana in Colorado occurred on April 6, 2014. The sale was made at the Denver-based dispensary, 3D Cannabis Center, after the legalization of recreational marijuana in the state in 2012.

3. On April 6, 1904, the Colorado state legislature created Mesa Verde National Park. The park is home to over 5,000 archaeological sites, including ancient cliff dwellings, making it one of the most significant archaeological areas in the United States.

4. On April 6, 1935, the construction of the Hoover Dam was completed. The dam, located on the Colorado River on the border between Arizona and Nevada, was built as part of a massive public works project during the Great Depression.

5. The first-ever U.S. patent for a snowplow was issued to William P. Murphy of Denver, Colorado, on April 6, 1920. Murphy's design revolutionized snow removal on roads and highways, making it easier and safer for people to travel through winter conditions.