1. The decline and fall of the Roman Empire.
3. The Spanish Inquisition.
4. The failure of Tom Cruise's marriage.
5. The sinking of The Titanic.
6. Original Sin.
8. Custer's Last Stand.
9. Everything that happened during George W. Bush's Administration.
10. Everything that happened during the Adolf Hitler Administration.
12. The San Francisco Earthquake.
13. The break-up of The Beatles.
14. The crash of The Hindenburg.
16. The Boston Massacre.
17. The extinction of the dinosaurs.
18. The Vietnam War
19. Lower back pain.
20. Erectile Dysfunction.
21. Mitt Romney's Swiss bank account.
23. The destruction of Pompeii.
25. All car accidents.
26. The stock market crash of 1929.
27. The Lincoln Assassination.
30. The fact that July Fourth fell on a Wednesday this year.
HuffPost Entertainment is your one-stop shop for celebrity news, hilarious late-night bits, industry and awards coverage and more — sent right to your inbox six days a week. Learn more