Opened in 537AD, the Hagia Sophia was the seat of the Eastern Orthodox church for nearly a millennium. It was later converted into a mosque, and in 1931, Mustafa Kemal Ataturk had it turned into a museum, banning all overt worship.
Now, Muslim groups in Turkey are gaining momentum in their bid to turn the world-famous Hagia Sophia back into a mosque - but some are concerned this is another instance of the government trying to push for a religious state.
Al Jazeera's Anita McNaught reports from Istanbul.
Source: Al Jazeera