Around 51 million Turkish people are eligible to take part in a historic referendum on whether to give sweeping new powers to their president.
The polls show it is a very tight race with the yes and no campaigns neck and neck.
Polling stations have opened for Sunday's referendum, which is likely to be decided by people who will not make up their minds until they reach the ballot box.
The country's state of emergency and a wave of terror attacks have taken their toll on the economy and given President Recep Tayyip Erdogan a reason to say he needs greater powers to keep the country safe.
Accountant Ali Telcik is the kind of voter President Erdogan has to win round if he is to secure victory in the historic vote.
:: Turkish referendum: Will dictatorship follow?
He supports the ruling AK party but says he will not back it in the referendum.
He told Sky News: "I don't think the referendum is necessary. We don't need it. I don't think it's going to solve any of our problems and it's just creating an atmosphere of tension."
Tour guide Onel Akalin says most visitors now are from the Arab world and western tourists are staying away.
Despite the stability President Erdogan is offering, he says he does not support giving him dictator-like authority.
Turkey's main opposition party knows it needs to get out the vote.
Ali Narin of the CHP opposition party said: "There are many people from different political views who've come together to support the no vote.
"I believe we can win but it will depend on the undecided voters."