Istanbul: Gülhane - Topkapi Palace

After a thorough restoration during the Republican era, Topkapi Palace was turned into a museum.
The towered outer entrance of the palace, the Bab-i Hümayun entrance, comes down from the time of Sultan Mehmet.
Entering from the Bab-i Hümayun, one reaches the oldest church of the Byzantine period, St. Irene.
After the conquest it was used as the armoury of the Janisseries soldiers