Both the "Yes" (to change) and "No" (to continue the existing system) have made intense efforts to sway undecided voters in the country's landmark referendum on April 16.

People wave Turkish flags as they attend a "Yes" campaign rally in the Etimesgut district of Ankara, on April 14, 2017.
People wave Turkish flags as they attend a "Yes" campaign rally in the Etimesgut district of Ankara, on April 14, 2017.

Turkey is preparing to vote in Sunday's landmark referendum that will decide the country's future by determining whether to change to a presidential system of governance or stick to the existing parliamentary system.

Some 55 million people are eligible to vote at 167,140 polling stations across the nation. Turkish voters abroad have already cast their ballots.

Campaigning must end at 1500 GMT on Saturday and both the "Yes" (to change) and "No" (to continue the existing system) supporters have made intense efforts during the past few weeks to sway undecided voters.

Here is a look at the campaigning from both sides across the country.

"Yes" stickers with pictures of Turkish President Tayyip Erdogan on a bus stop, in Istanbul, Turkey April 14, 2017. (Reuters)
Supporters of the opposition Peoples' Democratic Party (HDP) and of the
Supporters of the opposition Peoples' Democratic Party (HDP) and of the "Hayir" ('No') campaign attend a rally for the upcoming referendum in Istanbul, on April 8, 2017. (AFP/archive)
Supporters of Turkish President Recep Tayyip Erdogan wave flags during a
Supporters of Turkish President Recep Tayyip Erdogan wave flags during a "Yes" rally for the upcoming referendum in Konya, Turkey, April 14, 2017. (Reuters)
A woman cheers during a rally of the opposition Peoples' Democratic Party (
A woman cheers during a rally of the opposition Peoples' Democratic Party ("No") on the eve of the constitutional referendum, on April 15, 2017 in Diyarbakir. (AFP)
Supporters of President Erdogan wave Turkey's national flags and
Supporters of President Erdogan wave Turkey's national flags and "Yes" campaign flags during a rally for the upcoming referendum in Istanbul, Turkey, April 15, 2017. (Reuters)
Supporters of the opposition Peoples' Democratic Party (HDP) take part in a campaign rally for the
Supporters of the opposition Peoples' Democratic Party (HDP) take part in a campaign rally for the "No" (Hayir) vote, in Ankara on April 9, 2017. (AFP/Archive)
Billboards carrying pictures of Turkish President Erdogan (
Billboards carrying pictures of Turkish President Erdogan ("Yes") are seen during a rally for the upcoming referendum in Istanbul, Turkey, April 15, 2017. (Reuters)
"Hayir" ("No") supporters hold Turkish flags and leaflets for the upcoming referendum at a campaign point in Istanbul, Turkey, March 31, 2017. (Reuters/Archive)
Arab tourists are seen wearing caps inscribed with
Arab tourists are seen wearing caps inscribed with "Yes" in Uludag, April 9 2017. (AA)
"No" campaigners march along the Phosphorus in Istanbul to rally support in a historical vote on changing Turkey's political system, April 15,2017. #TurkeysChoice. (TRT World)
Source: TRTWorld and agencies