On every November the festival known as The Day of the Dead takes place. This popular Mexican holiday celebrates the return of the souls of the dead to Earth. People do many things to celebrate, including painting fake skulls in an artistic fashion.
Amy: We’re such tiny parts of your life, aren’t we? The Doctor: Amy, you are enormous parts of my life. And you are all I ever remember. <<--Because there's just so much in the Doctor's mind, and this encompasses the New Who only.