Years ago, for dinner on the evening of my first full day in Turkey, I went to a cafe on Istanbul’s Istiklal Caddesi. Istiklal is the busy outdoor pedestrian mall that anchors the city’s nightlife. I had spent the day touring the city’s headliner tourist sites — the Aya Sofya, the Blue Mosque, the Kapali Carsi.

I had sipped tea in the shadows of minarets. I had eaten doner, burrito-like wraps stuffed with thin slices of roasted mutton shaved from cylinders of meat on spits. I had guzzled entire cartons of ayran, the popular Turkish drink of yogurt, salt, and water.

My full day of sightseeing had left me feeling tired and overwhelmed. For dinner I wanted something bland and familiar. In the days to come there would be plenty of time to continue getting to know Turkey. I was in no mood to make this dinner that time. So instead of opting for uniquely Turkish food, I found a restaurant on Istiklal where I could get a simple club sandwich with french fries on the side.

I was not familiar with Istiklal, seeing it for the first time only minutes before sitting down to my club sandwich. As I ate, I was struck by the endless stream of people passing by on the street below. It was like someone had opened a fire hydrant on the street corner, but instead of releasing a torrent of water, the hydrant was spewing forth a river of people.

Now, even years after first witnessing Istiklal’s human river, I still marvel at its deep, relentless flow. When I stand on the street and watch people entering the river from its headwaters at Taksim Square, I feel like one of those kids I see in the movies, the kids who run around with their friends on a New York city street on a hot summer day, playing in water spraying from a street corner’s fire hydrant. I soak up the waves of humanity washing over me, the peoples’ laughter and light banter refreshing me after a day of intangible thoughts, words, ideas.

When I look at these people more closely, I realize that they all look different. I don’t mean some people have blond hair while others have black, or some people have light skin while others have dark. The differences are deeper, in the bone structures and the body types. It seems like every single person has a completely different shape.

These aren’t people who grew from the genetic stock of just a few people. These are people who grew from the genetic stocks of all the different peoples who over thousands of years have rampaged back and forth across this particular piece of land.

And yet these people all call themselves Turks.

Watching these Turks, these people who are a mish-mash of genetic stocks and yet identify with each other as if they were one, is a reminder that we humans do not migrate across the planet in discrete chunks, keeping our identities intact as we move about.

We like to think we do. We like to think Chinese have a land they call home, and when they come to Seattle they are the others. We like to think Poles have a land they call home, and when they come to London they are the others. We like to think Africans have a land they call home, and when they come to Istanbul they are the others.

But the lands on this planet do not care about the distinctions we humans make. The lands do not think of one group as the locals, and the others as the immigrants. We humans like to call our particular pieces of land home, but we are really just short-term renters.

When you travel, notice the people in front of you. Notice the Italians in Italy, the Germans in Germany, the Turks in Turkey. But think also of the people who came before them, and imagine the people who will come after them. Those people did, and will, have as legitimate a claim on the land as the people who occupy it today.

Travel helps you see the flow of people around the planet as an ocean current, as an infinite mixing process, not as the well-defined movement of discrete pieces on a chess board.