This is near the top of a Phota Tower Gallery, showing the last few photos and the door to the Next Gallery.  At this point, after the final Gallery photo, the spiral staircase veers off to climb up toward the exit.  If Explore is active, the door would soon be 'walked through' to visit the Next Gallery and continue viewing the next group of Album photos.  (The Space Bar can always be hit to pause any current activity, including Explore motion, and music -- press the Space Bar again to resume action.)