It is made up of high cusped arches and marble domes. More daring buildings soon followed, with great pillars supporting broad arches and domes. So too, the circular arches and the segmented spherical domes behind them. There are many arches, domes and vaults that show these influences. In the following years, most of the missing arches and spires were constructed. There still remain a minaret and some marble arches and columns. The building is crowned with projecting crenellated battlement, supported by small arches and corbels. Successive courses being used to build up walls, arches, and other architectural elements. Arches and barrel roofs are completely absent. It used stone arches and waterproof cement. Identifying traits being the squared up wheel arches and Paramount side mouldings. Other distinguishing features include flared front and rear wheel arches. It took the form of a circlet surmounted by ornaments and eight arches. Other examples include imperial triumphal arches (see List of Roman triumphal arches). Mosaics from the 2nd to 6th century show curtains suspended from rods spanning arches.