1. In 1783, the Maryland State House in Annapolis was the site of the Treaty of Paris, which officially ended the American Revolutionary War. Representatives from the United States, Great Britain, France, and Spain signed the agreement, which recognized American independence and established boundaries between the new nation and British North America.

2. On April 11, 1861, just days after the start of the Civil War, Confederate troops under General Robert E. Lee seized control of the United States Armory and Arsenal at Harpers Ferry, Virginia (now West Virginia). The raid was a significant blow to the Union war effort, as it deprived the North of critical weapons and supplies.

3. In 1889, Johns Hopkins University in Baltimore became the first university in the United States to offer a graduate degree in music. The school's Peabody Conservatory of Music had already been established for several decades, but the new degree program elevated the study of music to the same level as traditional academic disciplines.

4. The USS Maryland, a battleship commissioned in 1921, was named in honor of the state of Maryland. The ship saw action in World War II, including the Battle of Midway and the Battle of Leyte Gulf. After the war, the USS Maryland was used for atomic bomb testing before being decommissioned in 1947.

5. Thurgood Marshall, the first African American to serve on the United States Supreme Court, was born in Baltimore on April 11, 1908. Marshall was a prominent civil rights lawyer who argued several landmark cases before the Supreme Court, including Brown v. Board of Education (1954), which declared segregation in public schools to be unconstitutional.