List the unique features of Byzantine art and architecture

What will be an ideal response?

Byzantine church architects favored the Greek cross plan, by which all four arms of the structure were of equal length. At the crossing point rose a large and imposing dome. Inside the churches of Byzantium, the mosaic technique reached its artistic peak. A comparison of Byzantine mosaics with, for instance, any Roman paintings or sculptural reliefs underlines the vast differences between the aesthetic aims and purposes of Classical and Christian art. Whereas the Romans engaged a realistic narrative style to honor temporal authority, the Christians cultivated an abstract language of line and color to celebrate otherworldly glory.