So, although the positions are very strong and supporters of 3-D tend to be very critical of 2-D and viceversa, in this next slide I am trying to summarise the main pros and cons of 3-D with respect to 2-D solutions. First, on the pros side an advantage of adopting 3-D graphics is that they have further mapping possibilities. You can have for example objects which are closer or far away from the user, and this can be used to add further information to our visualization. Moreover when you exploit well the depth dimension that means that you are able to fit more things on the same screen, because things that are far away become smaller. So another advantage of 3-D graphics is that you can approach somehow the presentation problem we have mentioned before, because you fit more parts of your information visualization on the same screen. And finally another typical advantage of working with a 3-D space is that if your 3-D system is implemented well, you can exploit the natural - already known - navigation abilities of people, because people live in a 3-D world, so if you implement appropriately your 3-D space and you can walk on your visualization, you can pick up things, you can move around your head, then the user can reapply her basic navigation abilities coming from the real world.