1. Birth of John Shields: On April 20, 1748, John Shields, a prominent figure in Maryland politics during the Revolutionary period, was born in County Tyrone, Ireland. Shields served as a delegate to the Continental Congress for Maryland and helped draft the Articles of Confederation.

2. Burning of the Peggy Stewart: On April 20, 1774, a Maryland ship named the Peggy Stewart was burned in Annapolis as a protest against the British taxation of tea. This event came to be known as the "Annapolis Tea Party" and is considered one of the early acts of resistance leading up to the American Revolution.

3. Harriet Tubman's Death: On April 20, 1913, Harriet Tubman, the famed Underground Railroad conductor and abolitionist, passed away at her home in Auburn, New York. Despite being born into slavery in Maryland, Tubman returned to the state multiple times to help others escape to freedom.

4. Formation of the Baltimore Colts: On April 20, 1953, the Baltimore Colts professional football team was officially established, joining the National Football League (NFL). The Colts would go on to win NFL championships in 1958 and 1959, cementing their place in Maryland sports history.

5. Baltimore Riots: On April 20, 2015, protests following the death of Freddie Gray turned violent, resulting in looting and arson in some parts of Baltimore. The riots led to a citywide curfew and National Guard deployment, and sparked national conversations about police brutality and racial injustice.