1. In 1826, the Maryland State Colonization Society was formed in Baltimore. The society aimed to promote the colonization of freed African Americans in Africa, specifically in what is now Liberia. This movement gained traction in Maryland and other states during the 1830s and 1840s as a way to deal with the divisive issue of slavery.

2. On December 2, 1941, the United States Navy commissioned the USS Baltimore, a heavy cruiser named after the city of Baltimore. The ship saw action during World War II and the Korean War before being decommissioned in 1956.

3. In 1975, the first section of the Baltimore Metro opened to the public. This rapid transit system serves the city of Baltimore and the surrounding suburbs, and has expanded over the years to include multiple lines and dozens of stations.

4. On December 2, 1980, the National Aquarium opened in Baltimore's Inner Harbor. This popular attraction features thousands of animals in a variety of habitats, and has become a major tourist destination and educational resource.

5. In 2017, Maryland became the first state in the country to impose a ban on the sale of foam food containers. The law, which goes into effect in July 2020, aims to reduce pollution and protect the environment by encouraging the use of more sustainable alternatives.