Cathedral of the Annunciation, or, as it is called, Metropoli, is one of the biggest Orthodox temples of Athens, located on Mitropoleos square. The construction of the Cathedral began on Christmas day in 1842. The first Foundation stone was laid by the king of Greece, Otto and Queen Amalia.

For the construction of huge walls of the Cathedral was used marble from 72 churches. Three architects participated in the design of the Cathedral. The original building was designed by Theophil von Hansen. After it was built the lower level of the building, due to lack of funds the construction was suspended. After a few years the construction of the Cathedral continued, the architect Dimitrios Sets. After his death the work was continued by French architect Francois Boulanger. 20 years later the work was completed. May 21, 1862 in the presence of the king and Queen, the Cathedral was consecrated in honor of the Annunciation of the Mother of God.

The Cathedral is a three-aisled domed Basilica 40 meters long, 20 meters wide and 24 meters in height. Architecture and interior design of the Cathedral was made primarily in the Greco-Byzantine style.

In the Cathedral are the tombs of two saints killed by the Turks. The first relics of the Saint Philotheos. He was martyred by the Turks in 1559 for the redemption of Greek women from the Turkish harems. The second is the tomb of the Patriarch of Constantinople Gregory V was hanged by the Turks during the rebellion for the independence of Greece. Until 1871 his remains were buried in Trinity Greek Church of Odessa, after which they moved to Athens.

In the square before the Cathedral are two statues. The first is the monument of the last Byzantine Emperor Constantine XI Paleologos (Dragas), the second Archbishop of Damascus (during the Second world war was the Archbishop of Athens, and in 1946 Regent of king George II and the Prime Minister of Greece).

Metropoli is the seat of the Bishop of Athens and all Greece and an important spiritual center of Greek Orthodoxy.