In the construction of three domes of Bibi-Khanym mosque, sophisticated in Timur's time, one important innovation was applied, it is Two-fold construction, where the internal dome hall neither by the form nor by height corresponds to the dome's shape from outside. Reason for this is that between inner ceiling and outer cupola is the hollow space. This dome construction allowed main hall of the mosque to be committed to the proportions and the aesthetics of the 30 m high interior above the mihrab, meanwhile 40 m high outer dome of the main building could be designed towards maximal impression and visibility. This scheme was applied also to the lateral dome structures that allowed making modest buildings the figuration tower-like structures with elegant melon-shaped and longitudinally ribbed outer domes.