Istanbul's Hagia Sophia ('Holy Wisdom'), or Ayasofya, is one of the world's most visited buildings. Yet, few visitors have any idea of its long and complex story, or why it has always been a place where history, religion and politics collide. In July 2020, Turkish President Erdoğan set off an explosive controversy by announcing that Hagia Sophia would now be modified into a mosque. This decision provoked fierce criticism from UNESCO because...