1. On May 14, 1884, the state of Iowa officially adopted its state flag. The flag features three vertical stripes of blue, white, and red, with a bald eagle holding a ribbon with the state motto "Our liberties we prize and our rights we will maintain" in its beak.

2. May 14, 1932, marked the opening of the Herbert Hoover Presidential Library and Museum in West Branch, Iowa. The museum honors the life and legacy of the 31st president, who was born in West Branch and lived there until age 11.

3. On May 14, 2008, the Iowa Supreme Court unanimously ruled that a state law banning same-sex marriage violated the Iowa Constitution's equal protection clause. This made Iowa the third state in the U.S. to allow same-sex marriage.

4. May 14, 1862, saw the start of the American Civil War Battle of Princeton, Iowa. The battle saw Union troops under General Samuel Curtis defeat a Confederate force under General Marmaduke, helping to secure control of western Missouri for the Union.

5. May 14, 1977, marked the opening of the National Mississippi River Museum and Aquarium in Dubuque, Iowa. The museum showcases the history, culture, and ecology of the Mississippi River and its surrounding areas, and features a large indoor aquarium with a variety of river wildlife.