Creating Artificial Landscapes

For more Photoshop practise, I've created some artificial landscapes by combining photographs to make a new 'environment'. Both were very quickly done, but I feel that they are quite effective examples of how Photoshop can be used to create landscapes.

This is a combination of a photograph of the Milky Way as a background with two layers on top, each containing an image of a marble, removed from their original backgrounds. 

This is an image of some fireworks with an image of the countryside over the top. Using the magic wand tool, I removed the blue sky from the countryside photo, and as I went into quite close detail, removing tiny pixels of blue from between the leaves of the tree so that the fireworks really appeared to be behind it, which tricks the viewer into almost believing the illusion.