11. Put your entire career on the line to expose corporate irresponsibility (not mine, but I very much sympathise..!) 

12. Learn to scuba dive

13. Encourage a child

14. Always remember to turn the lights off

15. Walk in an old forest alone big enough that you can't hear the traffic and for you to walk all day without reaching the edge. Dare to go off the path

16. Spend three days living in a rainforest

17. Take one of the world's great train journeys

18. Donate 10% of a year's income to conservation charities

19. Go on a safari

20. Visit the Holocaust Memorial Museum in Washington DC

In this group, I've done seven so far, a better score than for the previous ten. Keep them coming – only 80 to go…