Due to her geographic location, Istanbul has always been a settlement area from early ages onwards. And besides connecting the two continents, Europe and Asia, Istanbul has become a center where various cultures and religions are merged into and lived together.Istanbul of the day fits the definition of a great city, not only with her inhabitants and the area she covers but also with the variety of cultures and their ways of living. This cultural structure which enables a good number of elements that contradict with each other and yet exist together even one in another , is the product of an accumulation of about one thousand years. Although first settlements in Istanbul dates back to prehistoric times, permanent settlements, however, have started in the colonial period. Foundations of Istanbul of our days were laid during recent periods of the Roman Empire. Byzantium and Ottoman periods are the most significant stages in the history of Istanbul. In both of these periods, Istanbul preserved her features of being a political and religious center and became the religious center of both, the Christianity and the Islam. Therefore, she was ornamented with many great monuments with different purposes belonging to these two religions. Although Ankara has been elected to be the capital by the Republic period, Istanbul has conserved her characteristic of being a cultural capital. The First settlements forming the core of today’s city were carried out by Megarians in the 7th century BC. They run away from Greece invaded by Dors, crossed the Sea of Marmara in 680 BC and settled in the city they established with the name Chalcedon on the Cape of Moda in Kadiköy and were engaged in agriculture. Another branch of Megarians settled down in the vicinity of Sarayburnu under the leadership of Byzas (at the point of Seraglio) in 660 BC. They named this place “Byzantion”. They were engaged in Commerce. This area was seized by Persians in 513 BC, then by Spartans in 405 BC and by Antigers, one of the commanders of Alexander the Great, in 318 BC, and was completely under the rule of to Rome in 74 BC. It was within the boundaries of Bithynia Pontus State of Rome in 73 AD. In 330, Constantine I, Emperor of Rome, proclaimed the city as the capital. And the name Byzantion was changed to Constantinople. Then, with the adoption of Christianity, it became the most important cultural and artistic center of Christianity throughout the medieval age. Later on it became the political and economic center (in 395). After the partition of the Roman Empire in two parts, it became the capital of the Eastern Roman Empire (Byzantium Empire). New neighborhoods formed as a result of growth in the population of the town. Subjected to the aggression of the Huns in 440. During the periods of Anastasios I (491-518) and Justinianos I (527-565), it became the scene of civil wars and uprisings. Sycae which gained importance in the period of Justinianos I, was connected to the city with a bridge over the Golden Horn. The town was attacked by Sassanians and Avars in 7th century, by Bulgarians and Ârabs in ISTANBUL9the 8th century and by Russians and Bulgarians in 9th century, but they could not capture the town. Crusaders attacked and captured the town in 1204. They Damaged it immensly. The town was the capital of the Latin Empire till 1261. New trade relations emerged due to the Crusades. The Contatinople started collapsing faster and faster. The Ottomans sieged the town first in the periods of Beyazid I (13891402) and Murat II (1422). Mehmet II added the town to the lands of The Ottoman Empire in 1453. Capital of the Ottoman Empire, was moved from Adrianople to Contatinople. The city became the Capital of the Caliphate in Selim I’s period (1517). The name of the town became Istanbul. Fires and earthquakes damaged the town to a great extent, during The Balkan wars which started in 1912 with the dethronement of Abdülhamit II and World War I, the town was occupied and damaged immensely. After the establishment of TBMM (Great National Assembly of Turkey) in Ankara on 23 April 1920, Mehmet VI the last Ottoman Sultan left the town. The town was then placed under the control of the TBMM Government and liberated from occupation (6 October 1923). Afterwards, it became the cultural and artistic center of the republican period, which has been maintained up to today.Due to its geographical location, Istanbul has always been a settlement area from prehistorical times to present day. The city bears the characteristic of being the capital city of two Great Empires Byzantine and Ottoman. Therefore, it is one of the few cities which has had a rich, diverse, historical culture. Prehistorical settlements in Istanbul started with the Chalcolithic period. However , the Paleolithic culture has been found in the Yarimburgaz Cave of Kucukcekmece. In Kadikoy (Chalcedon) there are remains of buildings from the Phoenicians. Also, the remains of the walls of the town called Lygos (5500-3500 BC) were found. Stratification in the caves were found in cave excavations made by the Turkish History Association. In between Byzantine and Paleolithic settlements, Chalcolithic settlements were found. Also during the Fikirtepe excavations, findings from chalcolithic period were found. The architecture of the Pendik mound is not well known. Istanbul, with its natural beauty and rich history, is a citi with significant local and international tourism potential, and from this point of view is one of the most attractive cities of the world. Besides its natural beauties, Istanbul has a lot of historical structures remaining from the Byzantine and Ottoman periods. Especially the trio of Topkapi Palace, St Sophia Museum located in Sultanahmet and the Kariye Museum are the places which attract the most interest from foreign tourists. Over a million people visit the Topkapi Palace and the St Sophia Museum every year. Other tourist highlights include mosques such as Sultanahmet (Blue Mosque), Süleymaniye and magnificent palaces, fountains, tombs, as well as charities (such as roads, public water distribution points), Turkish baths; historical structures like churches, cisterns, and walls. remaining from Byzantine period.Istanbul is also important as a center for international commerce. In this way, the historical and economic value of the Grand Bazaar is significant. Approximately 7,000 tourists visit this market which has a surface area of 47,600 sq., 61 streets and about 3,600 shops also a coffee-house for tourists on daily basis.