Turkey has a European side, Thrace but most of its land is in Asia and known as Anatolia. The further you get from the European side the more interesting and exotic the towns seem. Ankara and Konya are both Anatolian.
Istanbul is no longer the capital of Turkey but it has a historic centre and is one of the worlds largest cities. Its half in Europe and half in Asia so there are plenty of different things to see.
The best thing about Turkey is its variety. History, both ancient and modern, astounding natural features, and a fascinating culture.