"I've yet to find any windows," Sansa says. "Which I don't think is useful so much as notable. All throughout the rooms I've been able to investigate, I've found no windows that actually look to the outside so I cannot determine the hour of the day and I cannot determine where we are."

It's a useful trick to keep a prisoner. Both Joffrey and Ramsay had used it to great effect with her in the past.