1. In 1939, the Jefferson Memorial was dedicated in Washington, DC. The memorial was built to honor Thomas Jefferson, the third president of the United States and the primary author of the Declaration of Independence.

2. In 1860, the Pony Express began its first run from St. Joseph, Missouri, to Sacramento, California. The Pony Express was a mail delivery service that used horseback riders and relay stations to carry mail between the East and West coasts.

3. In 1968, riots broke out in Washington, DC, following the assassination of civil rights leader Martin Luther King Jr. The riots lasted for several days and resulted in extensive property damage and multiple deaths.

4. In 1792, President George Washington laid the cornerstone for the United States Capitol building in Washington, DC. The Capitol has since become one of the most recognized symbols of American democracy.

5. In 1948, The Marshall Plan was signed into law by President Harry S. Truman. The Marshall Plan was a program of economic aid to help rebuild Europe following the devastation of World War II. The plan was named after Secretary of State George Marshall, who proposed the idea.