1. The first day of summer is June 21st, which is celebrated as the Summer Solstice. In Iowa, the Summer Solstice typically marks the beginning of warmer temperatures and longer days.

2. In 1855, the first bridge across the Mississippi River was completed at Dubuque, Iowa. The Quantrill's Raid in 1864 in Lawrence, Kansas, where William Quantrill and his Confederate raiders rode into the city, burning and looting buildings, many people who owned buildings or who were abolitionists left Lawrence and moved to Iowa.

3. On June 21, 1976, a massive rainstorm flooded much of eastern Iowa, causing severe damage and claiming the lives of eight people. This event is known as the "Big Thompson Flood," and it prompted significant improvements to Iowa's flood protection infrastructure and policies.

4. In 1948, the Iowa State College baseball team won the NCAA College World Series. This historic victory marked the first time that a team from Iowa had won a national championship in any sport.

5. On June 21, 1900, Iowa Governor Leslie M. Shaw resigned from his position to become the U.S. Secretary of the Treasury under President William McKinley. Shaw's tenure as Secretary of the Treasury was marked by sweeping financial reforms, including the creation of the modern U.S. banking system.