1. On July 20, 1864, during the Civil War, the Battle of Rutherford's Farm took place in Frederick County, Maryland. Confederate forces, led by General Stephen D. Ramseur, were able to repel a Union army attack, securing their position in the Shenandoah Valley.

2. In 1881, on July 20, a fire at the Baltimore and Ohio Railroad's Mount Clare Shops destroyed over 100 locomotives and caused over $1 million in damage. The shops were rebuilt and continued to be an important hub for railroad maintenance until their closure in the 1970s.

3. July 20, 1923, marked the opening of the Chesapeake Bay Bridge, connecting Maryland's eastern and western shores for the first time. The bridge allowed for easier travel and commerce across the state and remains an important transportation link to this day.

4. On July 20, 1969, Marylanders joined people around the world in watching as American astronaut Neil Armstrong became the first person to set foot on the moon. Armstrong's famous words, "That's one small step for man, one giant leap for mankind," continue to inspire generations.

5. In 2004, on July 20, the state of Maryland announced the completion of a major restoration project at Antietam National Battlefield, site of one of the bloodiest battles of the Civil War. The project included the restoration of key historic structures, as well as improvements to visitor facilities and interpretive exhibits.