Mother of God. This is believed to be the largest mosaic in any of the altar's apses in the world. It spreads on , of which Mother of God covers . 10 to 15 thousand of glass pieces are included in each . Other themes on the mosaic are the Eucharist of the Apostles and representations of Saint Sava, Saint Basil of Ostrog, Saint Nikolaj of Ohrid and Žiča and Patriarch Pavle. Plans were made to fully paint the church's interior, which had bare walls for decades, partially by the mosaics, partially by the frescoes. After two years of preparation, in the summer of 2022, the large mosaic was placed on the tall ceiling above the altar and its apsis. It depicts Christ Enthroned, with two ethereal angels hovering above him. The mosaic is also done by Radlović, and made from the 8.5 million pieces of baked Venetian glass. The church has three altars. The altar table is also in marble with smaller mosaics on the front side. To the right of the altar is a smaller altar dedicated to the Holy Despot Stefan Lazarević (d. 1427), and the altar on the north side is dedicated to the feast day of the Transfiguration of the Lord. As one enters the church on the right side along the south wall of the church is the marble tomb of Emperor Stefan Dušan (r. 1331–55), designed by Dragomir Tadić. The emperor was originally buried in his endowment, the Monastery of the Holy Archangels near Prizren. The monastery laid in ruins for centuries. During the survey of the locality in 1927, historian discovered emperor's relics. He transported them to Skopje, and then handed them over to the Building of the Patriarchate in Belgrade. The relics rested there until 19 May 1968, when they were relocated to the St.Mark's Church. On the opposite, north side the tomb of Serbian Patriarch German (d. 1991) has been built in the same style and of the same material. There are mosaics above the emperor's and patriarch's tombs, done by Đuro Radlević: "Crowning of emperor Dušan", and "Eye of Providence", respectively. Inside is also a heavy beehive in the form of the scale model of the church. In the middle of the church underneath the central cupola is apolielei, a wheel chandelier, done in copper according to the design of Dragomir Tadić in 1969, and executed by academic sculptor