Since I forgot to take pictures of the entrance part I put you inside rather abruptly. And have you look up and see one of the sets of pillars supporting one of the four flat sections in the construction that supports the dome. This structure consists of alternating flat and concave portions, 8 in all. You can see part of the sectioned dome also, that is over the central part of the building, to the top of the picture is the ceiling of the corridor surrounding it.