1. On April 12, 1909, a band of robbers attempted to hold up the Colorado Midland train near Basalt. However, the train's conductor, William West, refused to stop and instead sped up the train. The robbers fired shots at the train but ultimately failed to rob it.

2. In 1971, on April 12, Colorado became the first state to adopt a "mini-Constitution" when voters approved a referendum to revise and modernize the state's constitution. The revised constitution included provisions such as tax limitations, citizen-initiated initiatives, and term limits for elected officials.

3. On April 12, 1945, President Franklin D. Roosevelt passed away at his home in Warm Springs, Georgia. In Colorado, the news of his death led to widespread mourning and many businesses closed as a sign of respect.

4. In 1984, on April 12, the Colorado Rockies played their first game at Mile High Stadium. The team, which had just joined the National League as an expansion team, lost to the Montreal Expos 7-1.

5. On April 12, 1862, the Battle of Apache Canyon took place near Santa Fe, New Mexico, which was then a part of the Colorado Territory. The battle was fought between Union troops and Confederate-loyal Texans and resulted in a Union victory. The battle was significant for securing the Santa Fe Trail as a supply route for Union troops during the Civil War.