1. 1790 - Maryland becomes the seventh state to ratify the United States Constitution.
On December 16, 1790, Maryland became the seventh state to ratify the United States Constitution, bringing the new federal government a step closer to being fully operational.

2. 1864 - The Battle of Nashville takes place during the American Civil War.
On December 16, 1864, the Battle of Nashville took place in Tennessee. Marylanders played a role in this battle, as several units from the state were part of the Union Army that defeated the Confederate forces.

3. 1907 - The Chesapeake Bay Bridge-Tunnel is first proposed.
On December 16, 1907, the idea for a Chesapeake Bay Bridge-Tunnel was first proposed by a Maryland engineer, W. T. Lee. This innovative idea eventually led to the construction of one of the world's most impressive engineering feats.

4. 1978 - Governor Harry R. Hughes signs the Chesapeake Bay Agreement into law.
On December 16, 1978, Governor Harry R. Hughes signed the Chesapeake Bay Agreement into law. This historic agreement brought together Maryland, Virginia, Pennsylvania, the District of Columbia, and the federal government to work together on improving the health of the Chesapeake Bay.

5. 2017 - The Baltimore Ravens win a crucial game against the Cleveland Browns.
On December 16, 2017, the Baltimore Ravens won a crucial game against the Cleveland Browns, keeping their playoff hopes alive. The game was significant for the Ravens and their fans, as it demonstrated the team's resilience and determination to succeed during a challenging season.