1. What is the capital of Spain?

2. What is the capital of Thailand?

3. What river runs through the city of Paris?

4. Why does NASA use the Atacama Desert for testing Mars rovers?

5. What is the term for the large, shifting sand dunes common in parts of the Sahara?

6. What unusual phenomenon happens to the Tonle Sap River during the monsoon season?

7. What narrow waterway connects the Mediterranean Sea to the Atlantic Ocean?

8. K2, the second-highest peak in the world, is part of which mountain range?

9. The Danube River passes through how many capital cities?

10. Which iconic plant species is used by geographers to define the boundaries of the Mojave Desert?

11. Why is the Huang He frequently referred to as the 'Yellow River'?

12. The Saguaro cactus, a symbol of the American West, is native only to which desert?

13. Which small country is located entirely within the Pyrenees mountain range?

14. The Murray-Darling Basin is vital to Australia primarily for which economic reason?

15. What gives the massive dunes of the Namib Sand Sea their distinctive red color?

16. Ancient Silk Road traders avoided the Taklamakan Desert by doing what?

17. The 'Gateway to Hell' (Darvaza Gas Crater) is located in which desert?

18. What primary factor gives the Yellow Sea its name?

19. Which iconic plant species is used as an indicator to define the boundaries of the Mojave Desert?

20. The Danakil Depression is located at the intersection of how many tectonic plates?