The background outside Tiny Tower is made of mountains and skyscrapers. The sky matches the time of day. But obviously when it is night it will be dark (Another Fact: You can also get a background (very rarely though) that has both Sky and Night

The highest building reaches to floor 12 on your Tiny Tower, while the highest mountain is 13 stories high. If you scroll down far enough, under the dirt is the sky. [Category:Gameplay]]