Entrance to the Cylindrical Core

A view of the opening (entrance) into a thick, but the hollow, cylindrical core that was originally 140 high.  The burial urn of Augustus was probably placed within this hollow core.   This picture was taken over a large block, that restricted access to the inner part of the cylindrical cord.

It looks like it was made out of Roman bricks and cement.  I assume that it originally was faced with marble.