1. The Battle of Monocacy occurred on June 17, 1864, during the American Civil War. Union forces under the command of Lew Wallace unsuccessfully tried to halt the advance of Confederate troops under Jubal A. Early on their way to attack Washington, D.C.

2. On June 17, 1775, the Second Continental Congress established the rank and pay for the Continental Army. It also appointed George Washington as its commander-in-chief.

3. In 1940, on June 17, the United States Navy commissioned the USS Yorktown (CV-5) aircraft carrier. It played an important role in World War II, participating in several key battles, including the Battle of Midway.

4. On June 17, 1930, famous Pennsylvanian aviator and inventor, Richard Byrd, made the first flight over the South Pole. He flew a Ford Trimotor airplane, appropriately named The Floyd Bennett, over the polar region, making history in the process.

5. On June 17, 1913, a violent shootout erupted in the town of Indiana, Pennsylvania, between striking coal miners and detectives hired by the coal company. The incident, known as the Indiana Massacre, left 26 people dead and is considered one of the deadliest labor conflicts in U.S. history.