Why do I have a black background in cycles render? I am creating a city in Blender and while rendering one of the buildings an odd thing happened with the background of cycles. Attached is an image of what I'm talking about although this doesn't truly matter because this model is going to be put into a larger model and not rendered alone, but I was curious because this is a distracting problem.
 
Here's what cycles normally looks like. I know the model is very incomplete and has no lighting, but I needed something to show.
 
If anyone knows what is going on please tell me.

Thanks
Under properties, got to World settings>Surface and change to color to the one you want.