1. In 1865, the first post-Civil War convention of African Americans in Ohio was held in Columbus. Attendees included prominent figures such as Frederick Douglass and Mary Church Terrell.

2. June 28, 1914 marked the assassination of Archduke Franz Ferdinand of Austria, an event that would eventually lead to the beginning of World War I. While this did not occur in Ohio, many Ohioans would go on to fight in the war.

3. In 1972, Ohio University became the first university in the United States to offer a degree in Environmental Studies, highlighting the state's commitment to environmental conservation.

4. On June 28, 1979, a partial meltdown occurred at the Three Mile Island nuclear power plant in Pennsylvania, just 200 miles from Ohio. This incident raised concerns about nuclear power safety and led to increased regulation and scrutiny of the industry.

5. June 28, 2015 marked the historic Supreme Court decision legalizing same-sex marriage nationwide. Ohio was one of the states where a key case in this decision was heard, with Obergefell v. Hodges originating in Cincinnati.