Materials used in vaults and vault doors have changed as well. She was buried in Maria Theresa's vault in the Imperial Crypt Vaults in Vienna. Inside are spiral staircases ascending to the clerestory and the vaults of the naves. These were built into natural caves or stone vaults. Frescoes were applied to the vaults and walls of churches. The use of brick vaults and domes in aboveground Han structures is unknown. Arches can also be configured to produce vaults and arcades. There is also gold leaf on the vaults and walls. Noailles also strengthened the buttresses, galleries, terraces, and vaults. In buildings with sexpartite vaults, they sometimes alternated with piers. The technique of building high vaults in masonry was revived. The piers, the arcades, the galleries, the vaults and the portals, all evolved. It is decorated with mosaics, in keeping with the choir vaults. An example is the thicker walls used in the case of barrel or continuous vaults. It is divided into two naves with Gothic rib vaults.