Associated Press

On June 18, 1778, American forces entered Philadelphia as the British withdrew during the Revolutionary War.

In 1812, the War of 1812 began as the United States Congress approved, and President James Madison signed, a declaration of war against Britain.

In 1815, Napoleon Bonaparte met defeat at Waterloo as British and Prussian troops defeated the French in Belgium.

In 1940, during World War II, British Prime Minister Winston Churchill urged his countrymen to conduct themselves in a manner that would prompt future generations to say, “This was their finest hour.”

In 1971, Southwest Airlines began operations, with flights between Dallas and San Antonio and Dallas and Houston.

In 2018, President Donald Trump announced the creation of the “Space Force” military branch.