1. On August 18, 1846, Iowa became the 29th state to join the United States. William Henry Harrison was the first Governor of Iowa.

2. On August 18, 1896, a tornado swept through the town of Pomeroy in northwest Iowa, causing significant damage and killing several people. The tornado was part of a outbreak that affected many parts of the Midwest.

3. On August 18, 1977, Elvis Presley passed away at his home in Memphis, Tennessee. However, his influence on music and culture can still be felt in Iowa and around the world.

4. In 1960, on August 18th, Iowa native Johnny Carson began hosting the popular late-night talk show 'The Tonight Show', which he continued until 1992. Carson was born in Corning, Iowa and grew up in nearby Norfolk.

5. On August 18, 1920, the 19th Amendment to the U.S. Constitution was ratified, granting women the right to vote. This was a significant milestone in American history, and many women in Iowa played a key role in the suffrage movement.