Country: Republic of Turkey
Coordinates: 41°00′49N 28°57′18E
Mayor: Kadir Topbas
Population: 14 million people
Time zone: EET (UTC +2), summer EEST (UTC +3)
Area code: +90 212 (European side)
+90 216 (Asian side)
Postal code: 34000 to 34850
Istanbul is the largest city in Turkey, constituting the country's economic, cultural, and historical heart. With a population of 13.9 million, the city forms one of the largest urban agglomerations in Europe and is the second-largest city in the world by population within city limits. Istanbul's vast area of 5,343 square kilometres (2,063 sq mi) is coterminous with Istanbul Province, of which the city is the administrative capital. Istanbul is a transcontinental city, straddling the Bosphorus—one of the world's busiest waterways—in north-western Turkey, between the Sea of Marmara and the Black Sea. Its commercial and historical centre lies in Europe, while a third of its population lives in Asia.
Founded on the Sarayburnu promontory around 660 BC as Byzantium, the city now known as Istanbul developed to become one of the most significant cities in history. For nearly sixteen centuries following its reestablishment as Constantinople in 330 AD, it served as the capital of four empires: the Roman Empire (330–395), the Byzantine Empire (395–1204 and 1261–1453), the Latin Empire (1204–1261), and the Ottoman Empire (1453–1922). It was instrumental in the advancement of Christianity during Roman and Byzantine times, before the Ottomans conquered the city in 1453 and transformed it into an Islamic stronghold and the seat of the last caliphate. Although the Republic of Turkey established its capital in Ankara, palaces and imperial mosques still line Istanbul's hills as visible reminders of the city's previous central role.
Istanbul's strategic position along the historic Silk Road, rail networks to Europe and the Middle East, and the only sea route between the Black Sea and the Mediterranean have helped foster an eclectic populace, although less so since the establishment of the Republic in 1923. Overlooked for the new capital during the interwar period, the city has since regained much of its prominence. The population of the city has increased tenfold since the 1950s, as migrants from across Anatolia have flocked to the metropolis and city limits have expanded to accommodate them. Arts festivals were established at the end of the 20th century, while infrastructure improvements have produced a complex transportation network.
Approximately 11.6 million foreign visitors arrived in Istanbul in 2012, two years after it was named a European Capital of Culture, making the city the world's fifth-most-popular tourist destination. The city's biggest draw remains its historic centre, partially listed as a UNESCO World Heritage Site, but its cultural and entertainment hub can be found across the city's natural harbour, the Golden Horn, in the Beyoglu district. Considered a global city, Istanbul is one of the fastest-growing metropolitan economies in the world. It hosts the headquarters of many Turkish companies and media outlets and accounts for more than a quarter of the country's gross domestic product. Hoping to capitalize on its revitalization and rapid expansion, Istanbul bid for the Summer Olympics five times in twenty years.
Neolithic artifacts, uncovered by archaeologists at the beginning of the 21st century, indicate that Istanbul's historic peninsula was settled as far back as the 7th millennium BC. That early settlement, important in the spread of the Neolithic Revolution from the Near East to Europe, lasted for almost a millennium before being inundated by slightly rising water levels. Before the archaeological discovery, conventional wisdom held that Thracian tribes, including the Phrygians, began settling on the Sarayburnu in the late 6th millennium BC. On the Asian side, artifacts originating around the 4th millennium BC have been found in Fikirtepe. 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 around 680 BC.
However, the history of Istanbul generally begins around 660 BC, when Greek settlers from Megara established Byzantium on the European side of the Bosphorus. The settlers proceeded to build an acropolis adjacent to the Golden Horn on the site of the early Thracian settlements, fuelling the nascent city's economy. 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 BC. Long allied with the Romans, Byzantium officially became a part of the Roman Empire in 73 AD.
Byzantium's decision to side with the usurper Pescennius Niger against Roman Emperor Septimius Severus cost it dearly; by the time it surrendered at the end of 195 AD, 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.
According to the updated Koppen–Geiger classification system, Istanbul has a borderline Mediterranean climate and humid subtropical climate. Since it has only two summer months with less than 40 millimetres (1.6 in) of rainfall, the city cannot be classified as solely Mediterranean or humid subtropical. Due to its vast size, diverse topography, and maritime location, Istanbul exhibits microclimates. Northern parts of the city express characteristics of an oceanic climate because of humidity from the Black Sea and the relatively high concentration of vegetation. The climate in the populated areas of the city in the south is warmer and less affected by humidity.
Only about fifteen days with measurable precipitation between June and August. Nevertheless, despite the low precipitation, the summer months also have the highest concentration of thunderstorms.
Istanbul is primarily known for its Byzantine and Ottoman architecture, but its buildings reflect the various peoples and empires that have previously ruled the city. Examples of Genoese and Roman architecture remain visible in Istanbul alongside their Ottoman counterparts. While nothing of the architecture of the classical Greek period has survived, Roman architecture has proved to be more durable. Obelisks from the Hippodrome of Constantinople are still visible in Sultanahmet Square, while a section of the Valens Aqueduct, constructed in the late 4th century, stands relatively intact at the western edge of the Fatih district. The Column of Constantine, erected in 330 AD to mark the new Roman capital, still stands not far from the Hippodrome.
Early Byzantine architecture followed the classical Roman model of domes and arches, but improved upon these elements, as in the Church of the Saints Sergius and Bacchus. The oldest surviving Byzantine church in Istanbul—albeit in ruins—is the Monastery of Stoudios (later converted into the Imrahor Mosque), which was built in 454. After the recapture of Constantinople in 1261, the Byzantines enlarged two of the most important churches still extant, Chora Church and Pammakaristos Church. Still, the pinnacle of Byzantine architecture, and one of Istanbul's most iconic structures, is the Hagia Sophia. Topped by a dome 31 meters (102 ft) in diameter, the Hagia Sophia stood as the world's largest cathedral for more than a thousand years, before being converted into a mosque and, as it stands now, a museum.
Istanbul has numerous shopping centres, from the historic to the modern. The Grand Bazaar, in operation since 1461, is among the world's oldest and largest covered markets. Mahmutpasha Bazaar is an open-air market extending between the Grand Bazaar and the Egyptian Bazaar, which has been Istanbul's major spice market since 1660. Galleria Atakoy ushered in the age of modern shopping malls in Turkey when it opened in 1987. Since then, malls have become major shopping centres outside the historic peninsula. Akmerkez was awarded the titles of "Europe's best" and "World's best" shopping mall by the International Council of Shopping Centers in 1995 and 1996; Istanbul Cevahir has been one of the continent's largest since opening in 2005; while Kenyon won the Cityscape Architectural Review Award in the Commercial Built category in 2006. Abdi İpekci Street in Nisantası and Bagdat Avenueon the Anatolian side of the city have evolved into high-end shopping districts.
Aside from typical Turkish cuisine like kebab, Istanbul is also famous for its historic seafood restaurants. Many of the city's most popular and upscale seafood restaurants line the shores of the Bosphorus, while the Kumkapı neighbourhood along the Sea of Marmara has a pedestrian zone that hosts around fifty fish restaurants. The Princes' Islands, 15 kilometres (9 mi) from the city centre, are also popular for their seafood restaurants. Because of their restaurants, historic summer mansions, and tranquil, car-free streets, the Princes' Islands are a popular vacation destination among foreign tourists