Serbethane Cafe & Restaurant is a really great venue to be found at Sultanahmet Mah. Kabasakal Cad.Arasta Carsisi, no: 117 Sultanahmet, Istanbul, Turkey.
We visited Serbethane two nights in a row, before returning home, and couldn’t help noticing the tunnel below which leads through to Hagia Sophia.
Andrew Harvard Photography 
Beautiful!
What a great shot! Have been to Hagia Sophia many times, such a magnificent site – now i will look out for this Serbethane tunnel, thanks for sharing!
Go to http://www.tripadvisor.com/Restaurant_Review-g293974-d1494195-Reviews-Serbethane_Cafe_Restaurant-Istanbul.html at night of course and young Amed (the manager) will show you