1. In 1848, the Smithsonian Institution was established by an act of Congress. The institution is named after British scientist James Smithson, who left his fortune to the United States to establish "an establishment for the increase and diffusion of knowledge."

2. In 1898, the United States took control of Guam as part of the Spanish-American War. The island had been a Spanish colony since the 17th century.

3. In 1921, Congress passed the Willis-Campbell Act, which established the Bureau of the Budget. The agency was created to help the president prepare the federal budget and to supervise government expenditures.

4. In 1965, President Lyndon B. Johnson signed the Social Security Act amendments, which established the Medicare and Medicaid programs. These programs provide healthcare coverage for millions of Americans who are elderly, disabled, or low-income.

5. In 2004, the World War II Memorial was dedicated in Washington D.C. The memorial honors the 16 million Americans who served in the armed forces during World War II, and the more than 400,000 who died in the conflict.