The Metropolitan Cathedral of the Annunciation (Καθεδρικός Ναός Ευαγγελισμού της Θεοτόκου), popularly known as the Great Metropolis is the cathedral church of the Archbishopric of Athens and all of Greece.

On Christmas Day, 1842 Greek King Otto and Queen Amalia laid the the first cornerstone of the Metropolitan Cathedral of Athens and thus commenced its construction. Workers used marble from 72 demolished churches to build the cathedral's immense walls. Three architects and 20 years later, it was completed. On May 21, 1862, the cathedral was dedicated to the Annunciation of the Mother of God.

The cathedral is a three-aisled, domed basilica that measures 40 meters long, 20 meters wide and 24 meters high. It features two bell towers and an impressive dome. The interior of the church is decorated with numerous frescoes; the impressive iconostase dates from 1825.Inside are the tombs of two saints killed by the Ottoman Turks during the Ottoman period: Saint Philothei and Patriarch Gregory V.

The Cathedral is a significant landmark in the Greek Orthodox Church and remains the largest church in Athens. Today it is the main church in Athens and also serves as the archbishop's seat.