Answer:
1. Puma
2. Seven Hills of Rome
3. Red Panda
4. N/A
5. Fidel Castro
6. Pac man???
7. Smallpox
8. Democratic Republic of the Congo
9. Treaty of Rome
10. Albert Einstein
11. Model T.
12. Adolf H. (not proper name i don't think saying it is allowed)
13. Trinity
14. Lord Curzon
15. Jazz Singer
16. N/A
17. Kalaripayattu
18. The Louvre
19. Quote from George Gordon
20. Poem by William Blake
Sorry I don't know the answer for 16 and 4 I hope the rest helps though. :)