I’ve wanted to go to Turkey since I was 15 when I learn about the Hagia Sofia. Constantinople, the capital, is supposedly one of the best example city of adaptive reuse. It was the capitol of the eastern Roman Empire. Once a Christian city with Hagia Sofia as its Cathedral, it was eventually sacked by the Ottomans and later the Turks. It was rename Istanbul and predominantly muslim. Its religious architecture converted to serve a different use.
More info here: http://en.wikipedia.org/wiki/History_of_Istanbul
Throughout this trip, I was able to visit Istanbul, Cappadocia, and Pamukkale. Cappadocia has a collection of weird landscapes and “mushroom” like rock spires, where as Pamukkale has a collection of calcium carbonate hot spring travertines.