Istanbul, historically known as Byzantium and Constantinople is the largest city of Turkey. According to the address-based birth recording system of the Turkish Statistical Institute, the metropolitan municipality (province) of the city had a population of 13.26 million as of 2010, which is 17.98% of Turkey's population and the largest in Europe before Moscow. The last census data from 2000 puts its proper population at 8.8 million. Istanbul is a megacity, as well as the cultural, economic, and financial centre of Turkey. It is located on the Bosphorus Strait and encompasses the natural harbour known as the Golden Horn, in the northwest of the country. It extends both on the European (Thrace) and on the Asian (Anatolia) sides of the Bosphorus, and is thereby the only metropolis in the world that is situated on two continents. Istanbul is a designated alpha world city.
During its long history, Istanbul has served as the capital of the Roman Empire (330-395), the Eastern Roman (Byzantine) Empire (395-1204 and 1261-1453), the Latin Empire (1204-1261), and the Ottoman Empire (1453-1922). When the Republic of Turkey was proclaimed on 29 October 1923, Ankara, which had previously served as the headquarters of the Turkish national movement during the Turkish War of Independence, was chosen as the new Turkish State's capital. Istanbul was chosen as a joint European Capital of Culture for 2010 and the European Capital of Sports for 2012. Istanbul is currently bidding to host the 2020 Summer Olympics. The historic areas of the city were added to the UNESCO World Heritage List in 1985.
The city covers 39 districts of the Istanbul province.
Istanbul is located in northwestern Turkey within the Marmara Region on a total area of 5,343 square kilometers (2,063 sq mi). The Bosphorus, which connects the Sea of Marmara to the Black Sea, divides the city into a European side, comprising the historic and economic centers, and an Asian, Anatolian side; as such, Istanbul is one of the two bi-continental cities in Turkey among with Chanakkale. The city is further divided by the Golden Horn, a natural harbor bounding the peninsula where the former Byzantium and Constantinople were founded. In the late-19th century, a wharf was constructed in Galata at the mouth of the Golden Horn, replacing a sandy beach that once formed part of the inlet's coastline. The confluence of the Sea of Marmara, the Bosphorus, and the Golden Horn at the heart of present-day Istanbul has deterred attacking forces for thousands of years and still remains a prominent feature of the city's landscape.
The historic peninsula is said to be built on seven hills, each topped by an imperial mosque, surrounded by 22 kilometers (14 mi) of city walls; the largest of these hills is the site of Topkapi Palace on the Sarayburnu. Rising from the opposite side of the Golden Horn is another, conical hill, where the modern Beyoglu district is situated. Because of the topography, buildings were once constructed with the help of terraced retaining walls (some of which are still visible in older parts of the city), and roads in Beyoglu were laid out in the form of steps. Uskudar on the Asian side exhibits similarly hilly characteristics, with the terrain gradually extending down to the Bosphorus coast, but the landscape in Semsipasa and Ayazma is more abrupt, akin to a promontory. The highest point in Istanbul is Chamlica Hill (also on the Asian side), with an altitude of 288 meters (945 ft).
Istanbul is situated near the North Anatolian Fault on the boundary between the African and Eurasian plates. This fault zone, which runs from northern Anatolia to the Sea of Marmara, has been responsible for several deadly earthquakes throughout the city's history. Among the most devastating of these seismic events was the 1509 earthquake, which caused a tsunami that broke over the walls of the city, destroyed over 100 mosques, and killed more than 10,000 people. More recently, in 1999, an earthquake with its epicenter in nearby Izmit left 17,000 people dead, including 1,000 people in Istanbul's suburbs. Istanbulites remain concerned that an even more catastrophic seismic event may be in Istanbul's near future, as thousands of structures recently built to accommodate the city's rapidly increasing population may not have been constructed properly. Seismologists say the risk of a 7.6-magnitude earthquake striking Istanbul by 2030 is greater than sixty percent.
Byzantium is the first known name of the city. Around 660 BC, Greek settlers from the city-state of Megara founded a Doric colony on the present-day Istanbul, and named the new colony after their king, Byzas. After Constantine I (Constantine the Great) made the city the new eastern capital of the Roman Empire in 330 AD, the city became widely known as Constantinopolis or Constantinople, which, as the Latinised form, Konstantinoupolis, means the "City of Constantine". He also attempted to promote the name Nea Roma ("New Rome"), but this never caught on. Constantinople remained the official name of the city throughout the Byzantine period, and the most common name used for it in the West until the establishment of the Republic of Turkey.
By the 19th century, the city had acquired a number of names used by either foreigners or Turks. Europeans often used Stamboul alongside Constantinople to refer to the whole of the city, but Turks used the former name only to describe the historic peninsula between the Golden Horn and the Sea of Marmara. Pera was used to describe the area between the Golden Horn and the Bosphorus, but Turks also used the name Beyoglu, which is still in use today. However, with the Turkish Postal Service Law of 28 March 1930, the Turkish authorities formally requested foreigners to adopt Istanbul, a name in existence since the 10th century, as the sole name of the city within their own languages.
Etymologically, the name "Istanbul" derives from the Medieval Greek phrase which means "in the city" or "to the city". In modern Turkish, the name is written "Istanbul", with a dotted I, as the Turkish alphabet distinguishes between a dotted and dotless I. Also, while in English the stress is on the first syllable ("Is"), in Turkish it is on the second syllable ("tan"). Like Rome, Istanbul has been called "The City of Seven Hills" because the oldest part of the city is supposedly built on seven hills, each of which bears a historic mosque.
Recent construction of the Marmaray tunnel unearthed a Neolithic settlement underneath Yenikapi on Istanbul's peninsula. The discovery indicated that the peninsula was settled thousands of years earlier than previously thought. Thracian tribes established two settlements - Lygos and Semistra - on the Seraglio Point, near where Topkapi Palace now stands. On the Asian side, artifacts have been found in Fikirtepe (present-day Kadikoy) that date back to the Chalcolithic period. The same location was the site of a Phoenician trading post at the beginning of the 1st millennium BC as well as the town of Chalcedon, which was established by Greek settlers from Megara in 685 BCE.
However, the history of Istanbul generally begins around 660 BCE, when the settlers from Megara, under the command of King Byzas, established Byzantion (Latinised as Byzantium) on the European side of the Bosphorus. By the end of the century, an acropolis was established at the former locations of Lygos and Semistra, on the Seraglio Point. The city experienced a brief period of Persian rule at the turn of the 5th century BC, but the Greeks recaptured it during the Greco-Persian Wars. Byzantium then continued as part of the Athenian League and its successor, the Second Athenian Empire, before ultimately gaining independence in 355 BCE. Long protected by the Roman Republic, Byzantium officially became a part of the Roman Empire in AD 73.
Byzantium's decision to side with the usurper Pescennius Niger against Roman Emperor Septimus Severus cost it dearly; by the time it surrendered at the end of 195, two years of siege had left the city devastated. Still, five years later, Severus began to rebuild Byzantium, and the city regained - and, by some accounts, surpassed - its previous prosperity.
When Constantine I defeated Licinius at the Battle of Chrysopolis in September 324, he effectively became the emperor of the whole of the Roman Empire. Just two months later, Constantine laid out the plans for a new, Christian city to replace Byzantium. Intended to replace Nicomedia as the eastern capital of the empire, the city was named Nea Roma (New Rome); however, most simply called it Constantinople ("the city of Constantine"), a name that persisted into the 20th century. Six years later, on 11 May 330, Constantinople was proclaimed the capital of an empire that eventually became known as the Byzantine Empire or Eastern Roman Empire.
The establishment of Constantinople served as one of Constantine's most lasting accomplishments, shifting Roman power eastward and becoming a center of Greek culture and Christianity. Numerous churches were built across the city, including the Hagia Sofia, which remained the world's largest cathedral for a thousand years. The Ecumenical Patriarchate of Constantinople developed in the city, and its leader is still one of the foremost figures in the Greek Orthodox Church. Constantinople's location also ensured its existence would stand the test of time; for many centuries, its walls and seafront protected Europe against invaders from the east as well as from the advance of Islam. During most of the Middle Ages and the latter part of the Byzantine period, Constantinople was the largest and wealthiest city on the European continent, and during parts of this period the largest in the world.
The Fall of Constantinople in 1453 signaled the end of the Byzantine Empire. Constantinople began to decline after the Fourth Crusade, during which it was sacked and pillaged. The city subsequently became the center of the Latin Empire, created by Catholic crusaders to replace the Orthodox Byzantine Empire, which was divided into splinter states. However, the Latin Empire was short-lived, and the Byzantine Empire was restored, weakened, in 1261. Constantinople's churches, defenses, and basic services were in disrepair, and its population had dwindled to forty thousand from nearly half a million during the 9th century.
Various economic and military policies instituted by Andronikos II, such as the reduction of forces, weakened the empire and left it more vulnerable to attack. In the mid-14th century, the Ottoman Turks began a strategy by which they took smaller towns and cities over time, cutting off Constantinople's supply routes and strangling it slowly. Finally, on 29 May 1453, after an eight-week siege (during which the last Roman Emperor, Constantine XI, was killed), Sultan Mehmed II "the Conqueror" captured Constantinople and declared it the new capital of the Ottoman Empire. Hours later, the sultan rode to the Hagia Sofia and summoned an imam to proclaim the Islamic creed, converting the grand cathedral into an imperial mosque.
The Ottoman sultans ruled from the Topkapi Palace for centuries. Following the fall of Constantinople, Mehmed II immediately set out to revitalize the city, now also known as Istanbul. He invited and forcibly resettled many Muslims, Jews, and Christians from other parts of Anatolia into the city, creating a cosmopolitan society that persisted through much of the Ottoman period. By the end of the century, Istanbul had returned to a population of two hundred thousand, making it the second-largest city in Europe. Meanwhile, Mehmed II repaired the city's damaged infrastructure and began to build the Grand Bazaar. Also constructed during this period was Topkapi Palace, which served as the official residence of the sultan for four hundred years.
The Ottomans quickly transformed Constantinople from a bastion of Christianity to a symbol of Islamic culture. Religious foundations were established to fund the construction of grand imperial mosques, often adjoined by schools, hospitals, and public baths. Suleiman the Magnificent's reign from 1520 to 1566 was a period of especially great artistic and architectural achievements; chief architect Mimar Sinan designed the Suleymaniye Mosque and other grand buildings in the city, while Ottoman arts of ceramics, calligraphy and miniature flourished. The total population of Constantinople amounted to 570,000 by the end of the 18th century.
A period of rebellion at the start of the 19th century led to the rise of the progressive Sultan Mahmud II and eventually the Tanzimat period, which produced reforms that aligned the empire along Western European standards. Bridges across the Golden Horn were constructed during this period, and Istanbul was connected to the rest of the European railway network in the 1880s. The Tunnel, one of the world's oldest subterranean urban rail lines, opened in 1875; other modern facilities, such a stable water network, electricity, telephones, and trams, were gradually introduced to Istanbul over the following decades, although later than to other European cities.
Still, the modernization efforts were not enough to forestall the decline of the Ottoman regime. The early 20th century saw the Young Turk Revolution, which disposed of Sultan Abdul Hamid II, and a series of wars that plagued the ailing empire's capital. The last of these, World War I, resulted in the British, French, and Italian occupation of Istanbul. The final Ottoman sultan, Mehmed VI, was exiled in November 1922; the following year, the occupation of Istanbul ended with the signing of the Treaty of Lausanne and the recognition of the Republic of Turkey, which was declared by Mustafa Kemal Ataturk on 29 October 1923.
In the early years of the republic, Istanbul was overlooked in favor of the country's new capital, Ankara. However, starting from the late 1940s and early 1950s, Istanbul underwent great structural change, as new public squares (such as Taksim Square), boulevards, and avenues were constructed throughout the city, sometimes at the expense of historical buildings. In 1955, the Istanbul Pogrom targeted the city's ethnic Greek community. The pogrom greatly accelerated the emigration of the city's ethnic Greeks to Greece. The population of Istanbul began to rapidly increase in the 1970s, as people from Anatolia migrated to the city to find employment in the many new factories that were built on the outskirts of the sprawling metropolis. This sudden, sharp rise in the city's population caused a large demand for housing development, and many previously outlying villages and forests became engulfed into the greater metropolitan area of Istanbul. As a capital of empires, the city was not only an administrative, but also a religious center. The Patriarchate of Eastern Christians has been headquartered here since its establishment, and the largest early churches and monasteries of the Christian world rose in this city on top of the pagan temples. Within a century after the city was conquered, it was enriched with mosques, palaces, schools, baths and other architectural monuments that gave it a Turkish character, while some of the existing churches in ruins were repaired, altered and converted into mosques.
Between the 16th century when the Ottoman sultans acquired themselves the title of the "Caliph of Islam" and 1924, the first year of the Republic, Istanbul was also the headquarters of the Caliphate. More Jews settled in Istanbul than any other port, and here they built themselves a new and happy life after they were rescued from Spain by the Turks in the 15th century. Istanbul has always been a city of tolerance where mosques, churches and synagogues existed side by side. The city was adorned with a large number of dazzling and impressive works even during the period of decline of the Ottomans. During this time, the influence of European art made itself felt in the new palaces, while the northern slopes of the Golden Horn, Galata and Beyoglu districts assumed a European character. Even when the Empire, which was a party to World War I, collapsed and the young Republic that replaced it moved the capital to Ankara, Istanbul did not lose its significance. The haphazard development that began in the years following World War II and accelerated in the 1950s has unfortunately had a negative impact on the fabric of the old city, and while old wooden houses disappeared rapidly, concrete buildings proliferated. Istanbul experienced a population explosion due to immigration, and within a very short period it expanded far beyond the historical city walls. The areas inside the walls were invaded by workshops, mills and offices; even the new thoroughfares could not solve the traffic problems, and the inadequacy of the infrastructure gave rise to a sea pollution problem, starting with the Golden Horn.
With the initiatives for saving the city in the 1980s, Istanbul embarked on a process of restructuring on a scale unseen in its history. Thousands of buildings along the Golden Horn were demolished to make way for a green belt on its shores; parks and gardens were built on the land claimed by filling up the beaches of the Sea of Marmara. In order to prevent sea pollution drainage systems were completed and physical and biological wastewater treatment plants were erected; the use of natural gas for heating has considerably reduced air pollution. Efforts are continuing for the restoration of the Roman city walls, and Beyoglu, the main artery, was rescued by building a new avenue. Improvements were made in the general cleaning, maintenance, garbage collection fields and these services are now at Western European standards. Ring roads cross the Bosphorus over two suspension bridges to connect the two continents. The European side has now a fast tramway system and a subway, and comfort and speed has been ensured in sea transportation with the hydrofoil terminals built on the seashores. All industrial establishments on the historic peninsula have been moved to new facilities in the suburbs, and the new international bus terminal has reduced traffic intensity. The old jail and the first large concrete building of the city were given over to tourism and converted into 5-star hotels.
The city is growing dynamically and developing at full speed on an east-west axis along the shores of the Marmara.