While Monica explored the museum of Roman graves beneath St. Sofia (and snuck up to take prohibited photos in the church) I chatted with this young woman who was the ticket taker about Istanbul. She did her undergraduate thesis on the traditional coffeeshops of Istanbul -- living and working there for six months. I really liked her.
Shortly after we left the museum, she tracked us down and, on her way to meet her boss, gave us a mini-tour of Sofia.