PART 1 Unit 01. Greek Philosophers of the Golden Age Unit 02. The Age of Discovery Unit 03. Our Shifting Earth Unit 04. Dance Language Among Honey Bees Unit 05. The Invention of the Modern Printing Press PART 2 Unit 06. Decoding the Rosetta Stone Unit 07. The Great Depression Unit 08. Understanding Hurricanes Unit 09. What Are GMOs? Unit 10. The History of Salt PART 3 Unit 11. The Cultural Advances of Hellenism Unit 12. Impressionism Unit 13. The Great Barrier Reef Unit 14. The Frozen Continent Unit 15. The Birth of the Skyscraper PART 4 Unit 16. The Placebo Effect Unit 17. Greenwashing Unit 18. Predicting Volcanic Eruptions Unit 19. A Star is Born Unit 20. Inventing the "Talkie"