Doctor Who's Google Doodle

Google have celebrated the Doctor Who 50th Anniversary with a very special Doctor Who Google Doodle.
The search engine often has doodles to celebrate significant occassions and whilst they may only be around for a short period of time they are viewed by millions of people.
The Doctor Who Google Doodle complete with mini game was months in the making.
BBC Newsround visited Google HQ in California to see how it came about. 
Click here to view the video on the Newsround site.