Iranians went to the voting booth today, Friday, June 12th, for their 10th presidential election since the 1979 Islamic Revolution. Their decision today is largely whether to keep hard-line president Mahmoud Ahmadinejad in power for four more years, or to replace him with a reformist more open to loosening the country's Islamic restrictions and improving ties with the United States. Ahmadinejad's leading opponent is Mir Hossein Mousavi, a former Prime Minister of Iran. Mousavi's campaign was propelled in recent weeks by young voters using high-tech campaign tactics (over 66% of Iranians are under the age of 30). Iran's presidential elections are tightly controlled, and, once elected, the office holder has limited power, but it remains the highest position determined by popular vote. Collected here are several photos from the past few weeks in Iran. ( 35 photos total