Perhaps equal in architectural grandeur to the Blue Mosque the Süleymaniye Mosque might be a better draw because it’s almost entirely empty. It has similarly spectacular tiles, soaring domes/half-domes, glittering windows, and almost no people in it. Though it’s the largest mosque in the city and is supposedly as big of a sight to visit, it was lovely and quiet and gave you a moment to really enjoy the architectural and decorative achievements of the complex. They also have quite nice, clean bathrooms (which I don’t remember if they were pay bathrooms, really minimal if they were), so if you need one, it’s nice to know they’re there. While the Blue Mosque/Hagia Sophia double-whammy definitely astonishes for just being so damn impressive, the Süleymaniye Mosque wins for being a better visitor experience.