1. Maryland officially adopted "The Black-Eyed Susan" as its state flower on April 15, 1918. The flower is a species of wildflower that is commonly found in fields throughout the state.

2. On April 15, 1861, President Abraham Lincoln called for 75,000 volunteers to help put down the rebellion in the southern states, including Maryland. This decision led to riots in Baltimore and other cities throughout Maryland, as many residents opposed the call to arms.

3. On April 15, 1945, Baltimore's first modern freeway, the Jones Falls Expressway, opened to traffic. The expressway was designed to alleviate traffic congestion in the city and provide a faster route for commuters.

4. The Maryland Science Center, which is located in Baltimore's Inner Harbor, opened its doors for the first time on April 15, 1976. The center features interactive exhibits and hands-on activities for visitors of all ages, and is one of the most popular attractions in the city.

5. On April 15, 1912, the RMS Titanic sank in the North Atlantic Ocean after hitting an iceberg. Although Maryland was not directly involved in the sinking, several passengers and crew members from the state were aboard the ill-fated ship. Today, the Maryland Historical Society has several artifacts from the Titanic, including the life jacket worn by a prominent Baltimore businessman who survived the disaster.