In the back of the Yavuz Selim mosque there is the huge open-air Asparne cistern, 152 times 151 meters and with about 250.000 cubic meters of capacity. I was very surprised to find that in a side-street to the East (Ali Naki Sokak no. 2) there is a nicely restored former cistern, which is now used for seminars, conferences and such: the Sultan Sarnıcı or Sultan’s cistern. I was allowed to take pictures, and if I ever want to organize a meeting in Istanbul I now know where I’ll go.