Yesterday was the 50th Anniversary of the longest running science fiction TV show in history, Doctor Who. To help celebrate the occasion, BBC put together a well crafted 50th anniversary episode that was simulcast across TV and movie theater screens worldwide and setting a Guinness World Record as "the world's largest ever simulcast of a TV drama".

The Doctors embark on their greatest adventure in this 50th Anniversary Special: in 2013, something terrible is awakening in London’s National Gallery; in 1562, a murderous plot is afoot in Elizabethan England; and somewhere in space an ancient battle reaches its devastating conclusion. All of reality is at stake as the Doctor’s own dangerous past comes back to haunt him.

According to overnight figures, the episode was watched by 10.61 million viewers, with an average of 10.2 million but just in case you weren't among those viewers and would like to get yourself caught up, the episode has is now available via iTunes along with several other special videos to help to celebrate the occasion.

Additionally, you'll also find the one-off drama An Adventure in Space and Time that looks back at the history of how Doctor Who and the people involved with its early beginning starring David Bradley as William Hartnell, who portrayed the First Doctor.