Maiden's Tower is the symbol of Istanbul due to its unique location at the intersection point of the two continents Europe and Asia, 2500 years old history and legends that have been subject to many stories and poems through out the history.
Hagia Sophia ; ( Turkish : Ayasofya , from the Greek : Ἁγία Σοφία , " Holy Wisdom "; Latin : Sancta Sophia or Sancta Sapientia ) is a former patriarchal basilica , later a mosque , now a museum in Istanbul , Turkey . Famous in particular for its massive dome , it is considered the epitome of Byzantine architecture and to have "changed the history of architecture.“ It was the largest cathedral in the world for nearly a thousand years, until the completion of the Seville Cathedral in 1520. The current building was originally constructed as a church between 532 and 537 A.D. on the orders of the Byzantine Emperor Justinian .
The Topkapı Palace ( Turkish : Topkapı Sarayı ) or in Ottoman Turkish : طوپقپو سرايى , usually spelled "Topkapi" in English) is a palace in Istanbul , Turkey , which was the official and primary residence in the city of the Ottoman Sultans for 400 years of their 600-year reign, from 1465 to 1853.
THE HISTORY OF THE BASILICA CISTERN One of the magnificent historical constructions of Istanbul is the Basilica Cistern, located near south-west of Ayasofya (Hagia Sophia). This huge cistern, which was founded by Justinianus I, a Byzantine Empire (527-565), began to be called by the public ‘the Sinking Palace’ – and not without a reason, seeing the great number of marble columns arising out of the water. In place of the cistern was formerly found a great Basilica, which had probably been built in IIIrd or IVth century during the Early Roman Age to be used in commercial and legal affairs and scientific and artistic activities. (http://www.yerebatan.com/english/index.html)