Turkey illuminated Hagia Sophia – a former Byzantine church that was turned into a mosque – with a “There is no God but Allah” banner, known as a mahya, on Saturday evening to mark Laylat al-Qadr.
Mahyas, featuring religious verses or advice for good deeds, are a centuries-old Ramadan tradition from Ottoman times.
“There’s No God But Allah” (La ilahe illallah) lights stretched across the minarets of the mosque, which was lit by Istanbul Governor Ali Yerlikaya.
It will remain lit until the end of Ramadan.
Earlier this year, Turkish President Recep Tayyip Erdogan called his controversial decision the crown of 2020.