First off, we have all seen this one from The Netherlands (think green for a green world) Although it seems an interesting design at first, I am heartily tired of this stamp and hope it runs out of circulation soon.
This one from The Czech Republic is rather nice, except that the map of the world does not include Australia and New Zealand and other bits of Australasia. Trees are meant to walk be walked around so they are there on the other side. Perhaps two stamps, one each showing the half of the world might have been a nice idea. Nobody asked me, though. This stamp for the International Year of the Planet was issued in 2008 and engraved by Jaroslav Chadima