Ahead of Sunday's general election, the BBC's Sarah Rainsford travels to Kayseri and Izmir to report on how the country's secular system and its democracy are being tested by a shift in power towards religious-minded Turks.
At five o'clock most mornings, the elite of Kayseri are already up and working out. In the hills that surround the city they take a brisk two-hour hike to start the day.
Turkey's two lifestyles: one religious, one secular
"We always start very early," one man puffs. Striding alongside him are the city's mayor, its business leaders and its police chief. "That's the Anatolian people. They have lots of energy," he says.
Kayseri is a clean-living city, and it is also devout. In Turkey today it is pious places like this that are on the rise.
On the outskirts of the neat and tidy town, Ahmet Hasyuncu runs a successful yarn business. He's also head of an industrial estate that has doubled in size in four years and now houses more than 700 companies, most of them home-grown.
At its centre is a vast mosque. Each factory here has at least one prayer room for its workers.
"Kayseri is known as a conservative city, but it's entrepreneurial too," Mr Hasyuncu says, surrounded by swirling reels of white cotton on his factory floor.
"Our businessmen are reformist - open to change - and we keep our religion out of our work."
Most of Ahmet's trade is with the West.
Once a backwater, central Turkey - or Anatolia - seized advantage of the economic liberalisation of the 1980s to develop into a driving force of the national economy. Local businesses have become known as the "Anatolian Tigers".
Pious places like the town of Kayseri are on the rise
The region has always been religious. But now people like Mr Hasyuncu are prospering they are creating a new, conservative middle class and becoming more prominent.
In strictly secular Turkey, that makes some people nervous.
"Are we really a threat to the system?" asks Mr Hasyuncu, laughing at the suggestion. "Secular Turks are trying to label us as something we're not. It's like they're seeing nightmares."
If there is a symbol of all that worries secular Turks, it is the Islamic headscarf and in conservative Kayseri covered women are a common sight.
In one room of a smartly refurbished centre run by the city council, three girls study Islamic art, their flat-nibbed pens scratching across the paper. They say they cover their heads as an expression of their personal faith. But away from here, less religious Turks are convinced the headscarf represents an Islamic political agenda.
"We face this kind of attitude very often and it makes us very uncomfortable," Emine says. "I don't think my scarf is a threat to anyone. But what can we do? It would take a miracle to change things here."
At the last election, 54% of voters here helped elect the AK party into office. Foreign Minister Abdullah Gul is a local.
Kayseri promotes itself as proof that you can be a devout Muslim and still be secular and modern.
But the fact that religious conservatives have political power now worries some people elsewhere in the country.
In places like Izmir, secularism is sacred
That worry is felt in Izmir on the west coast, where in the summer locals pack the nightclubs and the bars. Women wear miniskirts and low-cut tops here without a second thought. And there's alcohol.
But Izmir people call themselves modern Muslims too and for them, it is secularism that is sacred - as introduced by Mustafa Kemal Ataturk. He banished religion from politics when he founded the republic.
"We need to protect our modern lifestyle. We don't want very religious or conservative people to govern us," says club manager Ali Korur, as loud music pumps out across the bay from his 24-hour beach club.
Mr Korur believes the secular system guarantees his freedom. The most popular political party here in his town is the Republican opposition CHP.
"We need a leader that takes us to the West not to the East," he explains.
Back in town, Hanri Benazus sorts through photographs of the leader who first turned Turkey to face the West.
"Ataturk really was a great man. Everything that is contemporary in Turkey is down to him," he says, pointing out pictures of Ataturk in a smart suit and hat, or skimpy swimming shorts.
"Some people worry his revolution is in danger, but I think people who are used to modern life will never return to the age of ignorance."
A young woman sports a poster of Ataturk at a rally in Izmir
But that fear is real for some.
When the AK party tried to put a devout man in the presidency, thousands took to the streets in protest carrying enormous national flags. One of the largest demonstrations was here in Izmir.
The government was forced to back down for now. But some suggest the crisis over the presidential election exposed a deeper division here.
"There may be two Turkeys in terms of lifestyle," concedes Professor Tanju Tosun of Izmir's Ege university.
"But step by step we are absorbing democratic values and learning to live together."
It is a delicate balancing act.
The two Turkeys have lived side by side for eight decades. But now power is swinging towards more religious-minded Turks, the country's secular system - and its democracy - are being tested.