Here are five interesting events that happened on May 4 in Colorado history:

1. In 1869, the Colorado Territorial Legislature passed a law allowing women to vote in school board elections, making Colorado the first place in the United States where women won the right to vote.

2. On May 4, 1901, a large explosion occurred at the American Smelting and Refining Company in Pueblo, killing several workers and causing significant damage to nearby buildings.

3. In 1973, the Colorado Rockies were officially admitted as an expansion team into the National Hockey League (NHL).

4. On May 4, 1996, a massive blizzard known as the "May Day Blizzard" hit the Front Range, causing significant damage and disrupting travel for several days.

5. In 2013, Colorado became the first state in the United States to legalize the use and sale of recreational marijuana through voter-approved Amendment 64.