The ancient Constantinople was founded on seven hills surrounded by the city walls, just like Old Rome. In fact it was called as Nova Roma, meaning New Rome. Six of them lie along the Golden Horn (today's Haliç), while the seventh lies alone about one kilometer south.
4th hill was by the Church of the Holy Apostles; within today's Fatih (Conqueror) Mosque area in Fatih district.
5th hill was by the Theotocos Pammakaristos monastery; within today's converted Fethiye Mosque - Sultan Selim Mosque - Greek
High school area.
6th hill was by the Blachernae Palace; within today's Tekfur Palace - Mihrimah Mosque area in Edirnekapi neighborhood. This was the highest of all seven of them (70 meters above sea level) and originally out of the Constantinian Wall, it had its own fortification until Justinian expanded the city walls. This was the Fourteenth Region of Constantinople.
7th hill was the Xerolophos Hill near the Constantinian Wall; within today's Samatya - Capa - Cerrahpasa areas in Kocamustafapasa neighborhood.
Besides these, some other hills outside of the city walls are: Taksim hill, Yusa hill in Beykoz district, Sehitlik (martyrdom in Turkish) hill in Rumelihisar neighborhood, Maden (mines) hill in Sariyer district, Karlitepe (snow) hill in Pasabahce neighborhood, Tepebasi hill and Fetihtepe hill in Beyoglu district, Hurriyet (freedom) hill in Sisli district, Gayrettepe neighborhood, Esentepe neighborhood, Kustepe neighborhood, Nurtepe hill in Kagithane district, Sirintepe hill in Seyrantepe neighborhood, Gultepe neighborhood, Celiktepe neighborhood, Fikirtepe hill in Kadikoy district, Goztepe neighborhood, Icadiye hill in Uskudar district, Sultantepe neighborhood, Nakkastepe hill and Buyuk (big) Camlica and Kucuk (small) Camlica hills (262 and 229 meters respectively) in Kadikoy district, and Aydos hill (537 meters) in Kartal district.