Istanbul is, perhaps, best seen through the eyes of a cinematographer: Imagine a city so chaotic, but whose characters travail along the banks of a slow-moving river; and imagine a soundtrack so incongruent you can hear modern techno music and Islamic chants within the same earshot. Location: Take a wide-angle lens, you'll need one. The city on the Bospharus which straddles Europe and Asia is big - very, very, very big. Official estimates range from 12 million to 20 million inhabitants, which is an unsurprising discrepancy for this city. There are so many discrepancies here, but one thing is for certain, this mega-city is overflowing with people. They're everywhere, on every street and in every cafÃ©, in all the floors of all the buildings, and even underground. Every sidewalk is packed to the brim, and spawns another sidewalk. So much has been written over the centuries about this ancient/modern city. Here are some recent observations: the air pollution from the millions of vehicles is suffocating, and everybody smokes, everywhere. You can hear people cough and wheeze almost everywhere you go and it's no surprise. The air in central Istanbul is not as unbreathable as downtown Bangkok, but its getting there. The only people not smoking were the runners in this past Sunday's annual Istanbul marathon, which included women sporting the latest in skin-tight running apparel running alongside headscarf-covered ladies. The thousands of policemen and women who lined the streets of the marathon were, however, smoking. The smell of burnt chestnuts adds to the tinge in the air, but you really have to taste these things: when served warm, they are delicious. Cellular antennas and mosque minarets compete for the skyline, with each broadcasting their own special content to the heavens above this massive city. The soundtrack: You are constantly hit with incongruous sounds in Istanbul: On a taxi ride to the largest mall in Europe, the Kanyon, the driver was playing the latest techno remixes on Radio Power 100FM; on the way back downtown in a different taxi the driver was listening to Islamic chanting on TGRT radio. To the Western ear, the Turkish language seems impenetrable. But since Istanbul is just as Western as it is Eastern, the DJs of Power FM mix English words into their jive before and after some songs, the same words young DJs all over the world use. As the ferry leaves its docking moor for a cruise along the Bospharus, the sounds of the muezzin preacher calling the faithful to prayer dominates the soundtrack, as dozens of mosques along the river's banks come alive in unison. Interspersed among these is the humming sound of 20 million people at busy cafes and restaurants; the market-men shouting about their wares, the cars and buses honking their horns, and millions of others going about their business. And talking about the mosques during non-prayer times, inside they are silent, islands of tranquility away from the bustling streets outside. An interesting observation about the mosques: some of them have closed-circuit surveillance cameras mounted inside them, placed there ostensibly by the staunchly secular state apparatus to keep an eye on the goings-on inside the places of worship, which in certain parts of the world, have turned into hotbeds of radicalization. The country is on the verge of war with Kurdish rebels in northern Iraq, and nationalistic fervor is manifest: the entire city is draped in Turkish flags, and Attaturk, their legendary leader, adorns every flag and every nationalistic symbol. There has been continuous habitation in Istanbul for the past 3,000 years, and the city, previously Byzantium and Constantinople, has seen probably more history than most cities in the world combined. These days too, there is always "an issue" in Turkey, always something to talk about, just like in Israel. And just like in Tel Aviv, the conversations in the street cafes and pubs near the central Taksim Square are always heated: Turkey and the EU. [When are they going to let us in?] Turkey and the Armenians. [Was there a genocide or wasn't there?] Turkey and the Kurds. [Terrorists or freedom fighters?] Turkey and the Greeks. [How are things going in Cyprus?] Attitudes to these political questions vary with age and culture, and you'll find different answers to them in Istanbul's various neighborhoods and quarters, but one thing unites them all: a sense that this city is at the very heart of the debate, the very epicenter of world events - driven on by people inside, or on the borders of, this city straddling Europe and Asia. The writer was a guest of Greenhouse - a development program for Mediterranean documentary filmmakers.