Window of the Eye

The opening in the highest tower of Barad-dûr, from which Sauron surveyed the lands of Middle-earth. The Window was said to face westward, towards Orodruin some forty miles away. Since Sauron's Eye was able to gaze in any direction, it seems that there may have been other Windows in the high tower of Barad-dûr, looking out to the north, east and south.