If you know me and you read this blog often enough, then you know I love Doctor Strange.
By the Vishanti, the name of my blog is the Sanctum Mattorum.
HOARY HOSTS OF HOGGOTH! BEHOLD!
THE SANCTUM SANCTORUM IN ALL ITS GLORY!
In it, you can see what could be the Orb of Agamotto in the foreground, next to Doctor Strange, as well as some bookshelves off to the side. This is his library and his center for meditation, the place where Doctor Strange hones his powers and studies his mystic arts.
And, obviously, prominently displayed, is the Window of the Worlds with the Seal of the Vishanti over it (also called the Anomaly Rue), offering the entire residence the protection of the Vishanti. This is, quite possibly, the safest place in the entire Marvel universe.
This picture appears to be the reverse angle of the earlier concept art that was released.
The aesthetic of the space appears to be the same, which would make sense that all of this would be up on this floor. To be sure, there are plenty of other rooms in the Sanctum Sanctorum, but this is the most important, the most crucial and certainly the most iconic.