1. On December 17, 1806, Zebulon Pike led an expedition that reached the base of what is now known as Pikes Peak. Although Pike did not reach the summit, the mountain eventually became a popular tourist attraction and a symbol of Colorado.
2. In 1861, December 17 became the date of Colorado's admission into the Union as the 38th state. This made Colorado the first state to be admitted after the beginning of the American Civil War.
3. On December 17, 1914, the Denver Post Building was dedicated in downtown Denver. At the time, it was the largest newspaper building west of the Mississippi River and played a significant role in the development of Denver's newspaper industry.
4. In 1967, December 17 was the date of a tragic plane crash near Steamboat Springs that killed all 22 passengers and crew members on board. The plane was carrying members of the Wichita State University football team, administrators, and supporters. The crash is still considered one of the worst tragedies in the history of college sports.
5. In 2013, December 17 was the date of the opening of the Union Station transit hub in downtown Denver. The historic building, which had fallen into disrepair over the years, underwent a major renovation to become a hub for light rail, commuter rail, and bus services in the region.