What you see in the "bottom view" consists of 3 bowls, the ground, sky and clouds. They are first set up as one object then copied individually and added into 3 separate objects, and later added into the scene.
Easy 360 degree horizons, oceans, cities. Here is a quick way of doing it all.
You can use your non-uniform-scale-tool to adjust depth of your ground layer uniformly- which effects your horizon lines height. You can also change the texture to sand, then add another bowl, add a water texture, make this bowl very shallow and align the top with the horizon of the ground and you have an ocean with depth. You will need to adjust the depth of your water bowl and the # of your texture tiling to give the allusion of distance.
(revised)
The sky layer is a solid color and can be left as is to produce a horizon line best for oceans as seen in "world dome". In the picture "ground layer ends stood up horizontal" the top-most points have been selected and first raised, then the Non-uniform-scale-tool used in top view to stand them up horizontal. You can then add tillable buildings/mountains/or maybe a tree line to surround your scene. If you have a fourth ocean layer made you can tile a island. Experiment with different layers and image types (png) to create these effects. Remember when using PNG on your sky or distant objects use "final" for your ALPHA mode. To do this go to your material-texture-MD menu, there you will see "Alpha Mode".
As seen in "almost no sunset", and "more sunset", using non-uniform-scale-tool to adjust the height of the sky bowl adjusts where the global shading is on the object, effecting the sunset. I will have to ask Steve if there is a better way of doing this.
I will reply here with the texture files for the Anim8or save!