- 1898: The USS Maine explodes in Havana Harbor, Cuba, triggering the Spanish-American War.
- 1925: The "Serum Run to Nome" delivers life-saving diphtheria serum to Nome, Alaska, in a daring dog sled relay.
- 1965: Canada adopts its iconic red-and-white maple leaf flag, replacing the Canadian Red Ensign.
- 1971: The United Kingdom and Ireland complete their decimal currency conversion ("Decimal Day").
- 1972: Sound recordings receive federal copyright protection in the United States for the first time.
- 1989: The Soviet Union completes its troop withdrawal from Afghanistan after a decade-long occupation.
- 2001: The first draft of the human genome is published, marking a major scientific achievement.
- 2003: The largest anti-war protest in history takes place globally, with millions demonstrating against the Iraq War.
What is the unique adaptation that allows hippos to spend long periods of time submerged in water?