Binbirdirek Cistern (Cistern of Philoxenos)

A Hidden Byzantine Treasure in Istanbul

By Niobe | Travel Inn Turkey

I was on my way towards the Grand Bazaar, walking close to the tram line, when something caught my attention.

On the left, I noticed what looked like a small caravan of people and equipment. It seemed that a film or television production was taking place on the street. Of course, curiosity is one of my permanent companions, so I had to stop and have a look. Perhaps I would even recognize one of the actors!

What impressed me most was not only the filming itself, but how incredibly organized the whole production was. There was a lady carefully ironing the actors' costumes, a buffet providing tea and coffee, the director and actors, patiently waiting for their scenes, and even someone holding a silver reflector frame to control the light reaching the camera.

My eyes made a quick tour of the scene — and then I noticed an open door.

Behind it was something completely different.

A glimpse into the underground.

It was the entrance to the Cistern of Philoxenos, also known as Binbirdirek Sarnici, one of Istanbul's remarkable Byzantine cisterns.

The name Philoxenos comes from the Greek φιλόξενος (philoxenos), meaning “friend to the stranger” or “hospitable to the foreigner.”

And suddenly, while standing there among the lights, cameras and actors, I was looking at another world — one that had existed beneath the streets of Istanbul for many centuries.

A city beneath the city

The Cistern of Philoxenos is generally identified with the Binbirdirek Cistern, located in the historic Sultanahmet area between the Forum of Constantine and the ancient Hippodrome. It is considered one of the largest surviving covered Byzantine cisterns in Istanbul.

The cistern is famous for its impressive forest of marble columns. Historical and archaeological sources record 224 columns, many constructed from two superimposed column sections. Some of the columns also preserve ancient Greek mason's marks.

The Turkish name Binbirdirek literally means “Thousand and One Columns.” But, as I discovered, there are not actually 1,001 columns inside. The name is an expression suggesting a great multitude rather than an exact count.

From filming on the street to Byzantine Istanbul

What fascinated me was the contrast.

Above the ground: cameras, actors, costumes, coffee, conversations and the controlled world of a modern film set.

Below the ground: enormous marble columns, vaulted spaces and the remains of a sophisticated water system that belonged to Constantinople.

I did not get the opportunity to enter that day. The security team was carefully controlling access, and I had somewhere else to go.

So I continued towards the Grand Bazaar — but the image of those columns stayed with me.

I still have not properly met the Cistern of Philoxenos from the inside.

For sure is on my list.

And perhaps that is one of the wonderful things about Istanbul: you can walk the same street hundreds of times and suddenly discover that there is another Istanbul beneath your feet.

How many cisterns are hiding beneath Istanbul?

This is the question I could not stop asking myself.

How many underground cisterns does this magical city have?

The answer is astonishing. Research has documented hundreds of ancient cisterns and reservoirs across Istanbul and the former Constantinople, including both enormous open-air reservoirs and smaller covered cisterns. One study has catalogued more than 200 Byzantine-era cisterns.

And perhaps that is why exploring Istanbul never really ends.

There is the Istanbul we see.

And then there is the Istanbul beneath it.

My next adventure? I think I know where I am going.

Until then, I will leave you with the same question that stayed in my mind as I walked away:

How many more hidden cisterns are waiting beneath the streets of this extraordinary city?

Niobe's Istanbul adventures are made more meaningful with my travel partner, Travel Inn Turkey, helping curious travellers discover the stories, history and hidden places of Turkey.