I have been to San Francisco three times. The first time, I was mesmerized by how beautiful California is. The second time, I was preoccupied with other things and the city passed me by. I have just returned from the third, and it has churned something in me.

Physically, there is not much to it. There are AI ads everywhere. There are people working on their laptops on Caltrain. There are the offices of all the products we use every day. That is about it. I did not meet or talk to the important people who make San Francisco what it is. I only saw the ads, the train and the buildings, and still the city did something to me.

Maybe that is the point. The ads are not written for everyone. They assume the person reading them is building something. On the train, people don’t wait to reach the office before they start working. And the products I have used for years come out of a building I can walk past. In most places these things feel far away, made by somebody else. Here they are made down the road, by people who take the same train.

So what does San Francisco want from people? I think it wants you to build. It takes for granted that you are working on something, and if you are not, you feel it. Nobody says this to you. The city says it by being the way it is. For me, the message is: be more ambitious, do more, start a company, or build the one you are in much further.

It is a bittersweet feeling. The push is exciting, and it is uneasy too, because it shows me how much more I could be doing. I brought the push home with me.

I have felt a city do this once before, in Srirangam. It is to Srivaishnavam what San Francisco is to tech. Physically it is temples everywhere, the houses of preceptors who lived there a thousand years ago, and the sleeping god. I went there for the first time after growing up, and the place was clearly bigger than me. It wants tradition from people, and it made me feel small, where San Francisco makes me feel I should do more.

I want a name for a place like this. I’ll call it a canonical city: the source of something. San Francisco for tech, Srirangam for Srivaishnavam. If you want to be serious about the thing, it is where you go. And if the thing is already yours, you arrive and the city is bigger than you.

Hearing about the city is the first part. I had heard about Srirangam all my life, and about San Francisco for as long as I have worked in software. By the time you arrive, the city has been built up in your head for years. But standing there physically is the thing. Something that existed only as an idea in your life suddenly has a place, with an ad, a train and a house on a street.

Paul Graham has a great essay, Cities and Ambition, about the messages great cities send. I agree with most of it. He writes about what a city tells everyone. I am writing about what it does to you when the thing is already yours.

Not every great city does this. In Cambridge I knew I should respect the MIT people, and I did, but that was all. New York felt like it should be one, but I didn’t get that vibe. Maybe it has too many things. London was a great trip, and I still don’t know what that city wants people to do. I think someone from the film industry would feel in LA what I felt in San Francisco. I can guess that, but I can’t feel it.

A canonical city does this only to people who are part of the thing, and only when they arrive ready. I was not ready for San Francisco the first two times.

It also fades. I have been to Srirangam many times since, and my sister lives there now. The bigness has come down a bit.

I think people should go around to many such cities and see which one churns something in them. A great trip does not tell you much, but the churn tells you what you care about.