Istanbul, known in ancient times as Constantinople, capital of the great Byzantine Empire, is beautifully memorialized in its crown jewel — the Hagia Sofia. Though it changed hands many times during its history, the sixth-century basilica turned mosque turned museum remained the world's largest cathedral for almost 1,000 years. The modern day Hagia shows off more of its Islamic roots — when originally converted to a mosque, the bells, altar, and other Christian elements were replaced by the classic mihrab, which indicates the direction of Mecca; a minbar, or pulpit; and minarets that continue to adorn the building. Since becoming a museum in 1935, the carpets have been removed to expose the marble floor and plaster has been removed from the walls to expose murals that had been covered for centuries. You and your grandchildren can see it as Emperor Justinian (482 to 565 A.D.) had envisioned.
Hand it over: The Hagia has changed its face over the countries, and the surrounding city has, too. Originally named Byzantium, it has become Constantinople; currently, it's known as Istanbul.