Emily Badger, writing for Atlantic Cities wrote  "At their most fundamental, cities are not really agglomerations of people; they’re agglomerations of connections between people." Mexico City is highly striking to me because these connections seem to be much more publicly  visible here than in the US, but also because these connections provide a safety net for weak and unstable political, economic, and judicial systems.

One of the numerous poor people selling pirated MP3 CDs on the metro, this grungy young guy, backpack stereo blasting the corridas of northern Mexico, gets the attention of a seated old woman. No words are exchanged. He hands her one of the CDs and she gives him a ten peso coin. He puts the coin back in her withered hands and continues on. I don’t know if he did it from charity or to gain sympathy for the charitable act to sell more CDs, but I was touched, as I often am, by the high levels of charity and compassion I see here in Mexico City.

I am tempted to theorize that poorer cities, especially those in developing countries, have inhabitants who are more compassionate to one another. This is not to say that everyone is an angel, there is more interpersonal brutality as well, but it seems as though these cities function largely based on interpersonal relationships and social networks, necessarily extending to strangers.

There are of course, numerous counter examples- notoriously like the woman hit by traffic in China and no one stopping to help her, and apparently the same is true in Mexico City as well. I've been told that if you hit someone and draw blood in Mexico, you're pretty much guaranteed to go to jail, which is a huge discouragement to both good samaritains who are afraid that police will arrest anyone who happens to be there, and a major incentive for the driver to flee as quickly as possible.

Perhaps its a difference between normal and exceptional interpersonal relationships. In the US, exceptional situtations make family of us all- the news is full of strangers saving people from burning buildings, spontaneous charity in the face of disasters. What kind of American would simply walk by someone bleeding on the ground?

Similarly, in the 1985 earthquake that struck Mexico City, the government did nothing in the immediate aftermath of the earthquake, so the residents of Mexico City  organized thier own resuce teams, mobilized private excavation equipment and dug each other out of the rubble.

But these are urban relationships in exceptional cases, not the day to day, normal functioning of the city.

Developed western cities, with well-functioning bureaucratic and urban systems and generally high standards, can afford to prioritize comfort and convenience to a certain extent. You can look the Starbucks up on your iPhone, and there’s always plenty of parking. There's no need to interact with anyone.

In the developing world, you have to ask for directions, and get tips about where it's safe to park, or which areas are dangerous, or if you can perhaps bribe your way out of a parking ticket. The visitor is dependent upon the passer by, and the passer by releases this information because he knows he also will need the aid and knowledge of strangers to navigate the city.

It’s almost a kind of an implicit urban social contract- it allows an exchange of knowledge and ability to close the gaps in the official system, without which, the entire system of the city comes to a screeching halt.

Compassion is the wrong word, it’s a greater and more active understanding of how reliant the people of the city are on each other. When the lights go out in the city, do you know and can you rely on your neighbor? I worry about the US in this regard.

Resilient cities are those whose systems are not purely mechanical. Governments will fail, infrastructure will fail, disease, famine, drought, and war will come as they have throughout human history. Society underpins the City- the soft network is the real infrastructure holding the city together.

As an aside, that’s also why I find all the TV shows about post-apocalyptic American life so disturbing. The scenario for these shows is something happens to the physical structure of life in the cities and society collapses. There is an implicit understanding of civilization as contingent on a physical basis rather than on a social one. It’s an understanding of cities as a collection of buildings with people in them and the accompanying systems to maintain their well being. With this mentality, if the city stops ‘functioning’ in the mechanistic sense, then it’s the end of the city, the end of society, time to stock up on guns and ammo, every man for himself.

Cities are like streets. No one blinks at the idea of entrusting strangers with their lives and lives of their children. Every day, people place their trust in ten thousand other people not to recklessly speed and hit them or swerve into their lane from the opposite direction.

Similarly, there is nothing that backs the dollar. There’s no gold, no silver, no wagon wheels. It’s a currency, one of the strongest in the world, based purely on trust and agreement between people that it has value. The built environment is the paper to the currency of the city.