Hagia Sofia (or Ayasofia) was founded as a Catholic church in the 6th century, and converted to a mosque when Istanbul was conquered in the 15th century. It is no longer a functioning mosque.
It is fascinating to see the massive round Arabic canvasses, thirty feet in diameter, surround the main chamber, while ancient Biblical mosaics adorn the walls. Light streams through the stained glass as a couple hundred tourists don’t overwhelm the beauty of the massive interior.
We walk upstairs through an ancient ramped passageway, the 1500 year old rock smoothed by what must be millions of shuffling feet over the centuries. The interior views are magnificent, but the feeling not as holy as the functional mosques.
A couple hundred yards west, we enter the Blue Mosque. It is close to closing time for visitors, not long before the second to last prayer of the day. Like all the great mosques of Istanbul, it is cavernous, heavily adorned with mandalas, centuries-old tile, subtle lighting, beautiful stained glass.