1. On 20 April 1902, the couple from your 26 December round isolated pure radium chloride after years of work. Name them.

2. On 20 April 2010, an explosion on an oil rig in the Gulf of Mexico caused one of the worst oil spills in history. Name the rig and the oil company.

3. On 20 April 1792, France declared war on Austria. Which song from your 25 April round was written in Strasbourg days later for the Army of the Rhine?

4. On 20 April 1862, the scientist from your 27 December round and Claude Bernard completed the first test of a heating process to stop liquids spoiling. What is it called?

5. On 20 April 1653, the Lord Protector from your 16 December round marched soldiers into Parliament and threw out the members. What was this parliament called?

6. Which charismatic politician became prime minister of Canada on 20 April 1968? His son later held the same job.

7. Late on 20 April 1972 (US time), Apollo 16 landed on the Moon. One of its astronauts left a photo of his family on the surface. Name him or his commander.

8. On 20 April 1534, a French explorer set sail from Saint-Malo on the first of his voyages to Canada. Who was he?

9. On 20 April 1918, the German fighter ace known as the "Red Baron" scored his 80th and final victory. What was his real name?

10. The French emperor captured at Sedan in your 4 September round was born on 20 April 1808. Who was he?

11. A Catalan surrealist painter and sculptor was born in Barcelona on 20 April 1893. Who was he?

12. On the very same day, 20 April 1893, an American silent comedian was born who is famous for hanging from a clock above a busy street. Name him and the film.

13. An American actress born on 20 April 1949 won Oscars for "Tootsie" and "Blue Sky", and was carried up a skyscraper in "King Kong". Who is she?

14. An English actor born on 20 April 1964 is famous for motion-capture performances, especially as Gollum. Who is he?

15. An American actor born on 20 April 1937 played Sulu in the series from your 8 September round. Who is he?

16. The author of "Dracula", from your November round, died on 20 April 1912. Why did his death get little attention in the newspapers?

17. An Ottawa war chief who led a rebellion against the British in the Great Lakes region was killed on 20 April 1769. Who was he?

18. On 20 April 1980, Fidel Castro announced that anyone who wanted to leave Cuba could go from one port. What was the mass exodus called?

19. On 20 April 2008, in Japan, who became the first woman to win an IndyCar race?

20. An American R&B singer born on 20 April 1951 had hits with "Never Too Much" and "Dance with My Father". Who was he?