The old city (Sultanahmet) measures approximately 23 km2, but the current municipal boundaries extend far beyond. The original peninsula city had seven hills, necessary for Constantine's "New Rome". Six of them are the tops of a long ridge above the Golden Horn; the other is a lonely hill in the southwest corner. Around its slopes are many mosques and other historical landmarks that were collectively designated as UNESCO World Heritage sites in 1985

Sevenhill City Istanbul

The Golden Horn, the Bosphorus, and the Sea of Marmara are the effective coastal areas of Istanbul. The Golden Horn is a valley filled with water for about 7 km. Early inhabitants saw the area of the present Golden Horn as antlers (golden horn: golden horn), but foreigners call it the Golden Horn (“Gulf”). The Bosphorus is the channel connecting the Black Sea to the Mediterranean Sea via the Sea of Marmara and the Dardanelles. The Golden Horn separates the old Istanbul (Fatih) in the south from the city of Beyoğlu in the north; The wider Bosphorus separates European Istanbul from the city's Asian side districts, Üsküdar (ancient Chrysopolis) and Kadıkoy (ancient Chalcedony). Pouring into one of the world's most important passages, the Black Sea waters flow south through the Bosphorus, but beneath them, the salty warm waters of the Mediterranean are pushed northward as a strong undercurrent passing through the same channel.

How is Climate in Istanbul

Northeaster; the north wind comes from the Black Sea, and from the Balkans from time to time during the winter months, it can cause an icy eruption that can freeze the Golden Horn and even the Bosphorus. A southwestern or southwestern wind can create storms in the Sea of ​​Marmara.

How is Settlement Type in Istanbul

Fire, earthquake, rebellion, and occupation had ravaged Istanbul many times, with more than 60 fires and countless earthquakes that were significant enough to go down in history. Still, these disasters did not wash away this city: today wide roads run through the historic quarters of the old city, and unpaved streets lined with old wooden houses coexist with modern high-rises, office parks. There are hundreds of shopping centers in the old city, albeit small, in Istanbul.

Some of the city walls of Istanbul remain. The land walls separating the peninsula from the mainland, the traces of the Ottoman Sultan 2. Mehmed in 1453, at the point called Topkapı at this time, is remembered. The city walls surrounding Istanbul are 7 km long and the inner part was protected by ditches at the time of its construction, it consists of double rows of walls built in 413 and the outer part built-in 447. The higher inner wall is about .9 meters high and 5 meters thick and is adorned with 18-meter towers about 55 meters apart. Although the outer walls of the walls are made of 92 towers, only 56 are still standing. The sea walls were built in 439. Only short sections of the walls remain along the Golden Horn. The strong Golden Horn walls had 110 towers and 14 gates. The ramparts, which stretched for about 8 km from Sarayburnu and along the Marmara Sea, curved at the bottom of the peninsula to join the land walls, had 188 towers; however, the walls were only 6 meters high, as the Marmara currents provide good protection against enemy attacks. Most of the city walls are still standing.

It reaches Beyoğlu by crossing the Galata and Atatürk bridges and the Golden Horn. Each day, before dawn, these bridges open and close to allow the passage of central openings to offshore vessels. The shores of the Golden Horn, served by ferries, are a chaotic region consisting of docks, warehouses, factories, and historical ruins. The ferry piers that operate within the city are next to the Galata Bridge. Today, Istanbul has three of the world's longest suspension bridges: July 15 Martyrs Bridge (1973 first Bosphorus Bridge), with a main span of 1,074 meters; Secondly, the Fatih Sultan Mehmet Bridge was built in 1988. It is 1,090 meters long; and lastly, Yavuz Sultan Selim Bridge was built at 1,408 meters in 2016. In 2013 and 2016, a tunnel was built under the Bosphorus for vehicle traffic.

Istiklal Street/Taksim/Beyoglu

Beyoğlu, which was regarded as a foreign neighborhood in the 10th century, is considered the modern part of the city today. War and fires have left only a small number of structures built before the 19th-century standing, the Galata tower in Taksim being one of them. There is a steep slope from the Golden Horn to Beyoğlu. A funicular line passes between Galata Bridge and Istiklal Street. Pera area has big hotels and restaurants, travel agencies, museums, theaters, opera consulates, and many Turkish government offices.

Galata Tower

The Galata region is a residential area for foreign traders (Genoese) who enjoy overseas privileges outside the city walls. After the Ottomans conquered the city in 1453, all foreigners who were not citizens of the empire were restricted to stay in this area. Today, around Istiklal Street, there are buildings of various nationalities, including schools, churches, and hospitals. Eventually, the Galata area became a very crowded place, so the buildings were moved up the hillside (up from Kabataş, Karaköy, Kasımpaşa). The most important settlement lived in the Pera region. Foreigners who wanted to visit the Topkapi Palace, where the Ottoman Empire had been ruled for centuries, could only do so in the company of one of the sultan's janissaries (elite soldiers).

Almost nothing remains of Byzantium, which was chosen by I.Constantine  known as the founder of the Eastern Roman Empire, as the new location of New Rome, and the powerful city he built there. Constantine's column, the burnt column (Çemberlitaş), connected by metal braces, still stands next to the Nuruosmaniye mosque complex, but there is no evidence that any structure in the city dates to his period. Constantine completed the Hippodrome begun by Septimius Severus but was expanded and rebuilt by his successors until the 5th century. Only its curved end remains with three columns along the central Spina: an Obelisk removed from Egypt by the Roman emperor I. Theodosius, the serpentine column's serpent heads discarded after the Battle of Plataea, in which the Greeks defeated the Persians in 479 BC.

Markianos Column / Fatih (Kıztaşı)

Among the numerous columns adorning Constantinople, the pedestal of the Emperor Arcadius column (383-408) is still standing in the Cerrahpaşa district; A column of the emperor Marcian (450-457), known as the Maiden Stone Column (Virgin) in Turkish, in the Fatih district; and in the grounds of Topkapi Palace (in Gulhane park), another emperor, II. We find a perfectly preserved Corinthian column, thought to date from the reign of Claudius (Goths; 268–270).

Golden Gate/Yedikule/Seven Towers

The Golden Gate is located in the Yedikule region as a victory gate dating from about 390. II. It was built for the defense of Theodosius, near the junction of the land and sea walls. The marble-covered pedestals of its two towers are still standing, with three arches decorated with columns between them.

Basilica Cistern

The aqueduct, which was built by Emperor Valens in 366 in order to protect the water flowing from Belgrad forests to Istanbul through aqueducts, and to reduce the water needs of the city in summer months, was built in limestone as two floors. Some of the huge open water cisterns of the Byzantine period now serve the gardens. Among the more than 80 closed cisterns that have survived to the present day, one of the most beautiful and mysterious structures of Istanbul is the Basilica Cistern or the Basilica Cistern, also known as the Basilica Cistern in Turkish. Near Hagia Sophia; Its 336 columns, two of which are supported by the head of Medusa (to protect it from bad energy), serve as a museum that attracts a significant number of visitors today.

Tekfur Palace

Almost the only preserved example of the architecture of Byzantine palaces in Istanbul is Tekfur Palace, also known as Blakhernai (Blakhernai) Palace. It is a three-story rectangular building made of limestone and brick with Byzantine patterns and lines. The Byzantine monument Tekfur Palace in Edirnekapı is currently operated as a museum by the Istanbul Metropolitan Municipality.