I made this over a month ago at work using the GIMP. I have two widescreen monitors and I wanted something cool for my wallpaper. I also use a program called UltraMon which lets me take full advantage of two monitors, allowing me to have different wallpapers on each screen or (in this case) one wallpaper spread across both. I just finished watching Gurren Lagann so I decided to put this together using two seperate images found on the internets. If I remember right, it took a couple of hours worth of editting to get the images to line up properly and look like one image.
I understand not many people would have a practical means of using this as wallpaper, but enjoy the HR at least.