1. Blizzard of 2003: On March 13, 2003, Colorado witnessed an unprecedented blizzard that brought more than 3 feet of snow to parts of the state. The storm caused widespread power outages, closed major highways, and resulted in several fatalities.

2. Columbine High School: On March 13, 1999, just weeks before the tragic shooting at Columbine High School in Littleton, Colorado, student Bryan Anderson was arrested outside the school for possessing a sawed-off shotgun.

3. Colorado National Guard: In 1913, on March 13th, the Colorado National Guard was mobilized to quell a labor dispute between striking miners and the Colorado Fuel & Iron Company in Ludlow, Colorado. The conflict escalated into the Ludlow Massacre, in which 20 people were killed, including 11 children.

4. Governor's Mansion: On March 13, 1908, construction began on the Colorado Governor's Mansion, which is located in Denver's Capitol Hill neighborhood. The mansion was designed by architect Willis A. Marean and is listed on the National Register of Historic Places.

5. Greenhorn Valley: On March 13, 1964, the small community of Greenhorn Valley, Colorado, was struck by a devastating tornado that caused extensive damage and resulted in several fatalities. The tornado was one of the most destructive in Colorado's history, with winds estimated to have reached over 200 mph.