On May 18, 1863, the Siege of Vicksburg began during the Civil War, ending with a Union victory on July 4.

In 1896, the U.S. Supreme Court, in Plessy v. Ferguson, endorsed “separate but equal” racial segregation. (The decision was reversed 58 years later by Brown v. Board of Education of Topeka.)

In 1933, President Franklin D. Roosevelt signed a measure creating the Tennessee Valley Authority, the largest U.S. public utility.

In 1980, Mount St. Helens in Washington state erupted, leaving an estimated 57 people dead or missing.

In 1998, the U.S. government filed an antitrust case against Microsoft, saying the software company had a “choke hold” on competitors that was denying consumers important choices about how they bought and used computers. (The Justice Department and Microsoft reached a settlement in 2001.)