Decorated by the architect Vedat Tek with Kütahya tiles and stained glass, this is Turkey's largest post office building. It is the historic communications centre from which, as Istanbul was occupied on 16 March 1920, the telegraph clerk Manastırlı Hamdi Bey reported events to Ankara minute by minute; you can still walk into its three-storey glass-vaulted inner courtyard and do your business there today.