I am trying to find out the significance of the door knockers in this picture from the Baha-ut Din Naqshband Complex outside Bukhara (photo taken circa 1911 by Prokudin Gorskii).
Baha-ut Din Naqshband Complex, Bukhara
It's hard to see the doorknockers from the thumbnail. I was curious, so I found the original from the Library of Congress website, and here's the link for anyone who wants to see them up close. There are, basically two dozen doorknockers of different shape and size; how curious! Perhaps it's a way of letting every follower know and announce their rank and place.