Originally a church, then a mosque and now a museum, the Hagia Sophia is Istanbul's most famous monument and one of the most important religious structures on the planet. For a millennium after its construction in the sixth century, the Hagia Sophia was the world’s largest cathedral. Its famed dome rests on an arcade of 40 arched windows and remains one of the largest in the world, standing 55 meters (182 feet) from floor level at its maximum. From Byzantine mosaics to calligraphic roundels and even scaffolding from ongoing restoration, layers of the building's history can be viewed all at once.
To get a first-person look inside, be sure to tap the blue Ayasofya (Hagia Sophia) location text above this image. Photo by @mashaer4u