1. In 1787, Maryland became the seventh state to ratify the United States Constitution, which established the framework for the federal government and remains the supreme law of the land.

2. On July 12, 1817, the groundbreaking ceremony for the Chesapeake and Ohio Canal was held in Georgetown, marking the beginning of construction on what would become an important transportation link between the Potomac River and the Midwest.

3. In 1864, during the Civil War, Confederate forces under General Jubal Early attacked Fort Stevens in Washington, D.C., which was defended in part by Union troops from Maryland. President Abraham Lincoln personally visited the fort during the battle, one of the closest to the nation's capital during the conflict.

4. On July 12, 1940, the first prototype of the Vought-Sikorsky VS-300 helicopter made its debut flight at Stratford, Connecticut, piloted by Igor Sikorsky, a Russian-born engineer and inventor who later established a subsidiary of his aircraft company in Maryland.

5. In 2013, NASA's New Horizons spacecraft, which had been launched from Cape Canaveral, Florida in 2006, made its closest approach to Pluto, providing the first detailed images and data about the distant dwarf planet. The mission was managed in part by the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.