1. Colorado achieved statehood. On December 31, 1875, President Grant signed a proclamation admitting Colorado as the 38th state.

2. The deadliest avalanche in US history occurred in Colorado. On December 31, 1913, a massive avalanche swept through the town of Wellington, killing 96 people on board a train that was stranded in the snow.

3. The historic Stanley Hotel opened its doors. On December 31, 1909, the iconic Stanley Hotel in Estes Park welcomed its first guests. The hotel served as inspiration for Stephen King's novel "The Shining."

4. The Denver Broncos won their first playoff game. On December 31, 1977, the Broncos defeated the Pittsburgh Steelers in their first playoff victory.

5. The first New Year's Eve Ball Drop in Denver took place. On December 31, 1993, the first New Year's Eve celebration featuring a ball drop was held in Denver's historic 16th Street Mall. The event has since become a beloved tradition in the city.