This was made by Eirik Solheim over the period of year using a camera pointing out his window hooked up to his computer.
"I placed my old SLR in our window in january last year. Hooked it up to our home server and gave it power through an adapter. Then I used software to control the camera. It has snapped one image every 30 minutes for one year now. "For further details the process on his blog http://eirikso.com/