For 1,000 years, the Hagia Sophia was the largest cathedral ever built (dwarfing all those Gothic cathedrals that came a mere 600-800 years later). Ironically, the greatest example of Orthodox Christian architecture became the preferred style for Turkish mosques, once you add the surrounding towers for prayer calls.
I’ve built this building quite a few times as a Civilization IV world wonder, but this is the first time I’ve been able to see it for real. Like the Taj Mahal, this is one of those places where pictures can’t capture the magic.