Renowned as one of the most beautiful buildings in the world, the spellbinding Byzantine glory of the Hagia Sophia Mosque (Aya Sofya) is not only one of the top things to do in Istanbul, but also in Turkey.
Built by the Byzantine Emperor Justinian in 537 CE, it is renowned as the Byzantine Empire's greatest architectural achievement and has remained the world's largest church for 1,000 years.
This bustling Mediterranean hub has something for everyone.
The two main beaches outside of town are sun-sloth heaven in summer and attract holidaymakers from across Europe. While the old town area, snug right in the center of town, with its cobblestone alleyways rimmed by creaky Ottoman-era mansions, is a wonderful place to explore.
One of Turkey's most famous natural wonders, the pure white travertine terraces of Pamukkale ("Cotton Castle" in English) cascade down the slope looking like an out-of-place snowfield amid the green landscape.
Although the travertines are themselves a highlight of a Turkey trip, the vast and rambling ruins of Greco-Roman Hierapolis, an ancient spa town, lie scattered across the summit of this calcite hill.
Turkey's best-preserved Ottoman town is a fabulously photogenic place of skinny winding alleys crammed with finely restored wooden mansions which were once the home of wealthy merchants and now have been transformed into boutique hotels and restaurants.
There's little to actually do in town. Instead this is a place to simply stroll the streets and admire the old world atmosphere.