The long wait has eventually finished.
It's been a tough task. I've never been so active on 591 blog as recently. I committed to take care of the "Earth" section, sending out invitations to all the photographers I know and getting in few weeks more than 100 answers from more than 50 people. This is not bad, provided I had to select 30 photographs from preferably thirty different people.
Now the selection task has finished. We have gathered our selections together and prepared the slideshow. Find a comfortable seat, on a sofa, on a long chair and click on the picture below: there are 120 pictures waiting to be seen. It will be a 10 minutes long break. A cup of tea could help to let you float through the large variety of interpretations that were given to each of the four topics.
I'm very happy to have contributed to this project. Next step should be a free downloadable PDF file collecting all the selected images.