 The 21st century, our century, is becoming the century of the city. For the first time in the history of our planet, more than half of human population is living in urban areas, and this is expected to grow to 70% in 40 years. Every week, more than a million people migrate to cities, driven by the promise of better lifestyle, better opportunities, but also generating several urban problems, such as traffic, pollution, segregation, just to name a few. If these problems grow with city size, we could imagine a green future. Can you imagine a future for our children where our cities collapse by their own growth? Well, I don't. Why? Because we have the technology to prevent this. It's called living technology. Living technology exhibits the properties of living systems. Living technology learns, evolves, adapts. It's robust. It self-organizes. In contrast, traditional technology is rigid. It cannot cope with changes in problems, and urban problems are changing constantly. So traditional technology offers only obsolete solutions. Living technology, like these flocks of birds, can adapt to changing problems. And it not only imitates nature. It behaves like nature. We can make our cities more livable by building our cities behave more like living systems. And living technology can help us solve several of the urban problems we have already. For example, mobility, which is a huge problem in most cities. How do you get people and goods from one place to another? It has really lots of components. It's a very complex problem. One of them is traffic lights. But living technology can coordinate traffic lights in a similar way to birds, and reducing waiting times to 50%. Real-time information systems can help us make wiser decisions. And living technology in public transportation systems can deliver performances that are better than the theoretical optimal of traditional technology. Our communications are everywhere. They help us communicate between ourselves and with our devices. But they're becoming so complex that they can only function excepting the properties of living systems. And this technology also enhances citizen participation, making our cities more democratic because each one of us can participate in our own governance. Urban nervous systems and urban immune systems can increase the safety and also the response to disasters. And sustainability is defined as the ability to endure. Our cities cannot endure functioning as factories. That is not sustainable. Our cities will only endure if they function as living systems. This is why we need living technology and this is why we have living technology now. Let me just illustrate what living technology can do with an example in public transportation. This applies to metros, to trains, to trams, to buses, even to elevators. Now, traditional technology tries to minimize waiting times of passengers at stations. And in order to do this, you must try to keep regular intervals between vehicles. So the problem is that this configuration is unstable. It's like an inverted pendulum. A small perturbation will drive it from that configuration. So it's very easy for vehicles to bunch up and this quickly leads to a collapse in the system. So these types of scenes are becoming more and more common in larger urban areas. And traditional technology cannot offer solutions for this problem. What about living technology? What can we do about this? Well, instead of trying to impose an order of control on the system, let's the system self-organize in a way similar to ant-colonial communication, the system can respond to local demand at each station and it can deliver performance better than the theoretical optimum. Now, how can something be better than the theoretical optimum? I mean, if the theory tells that this is the best we can do, and this system is performed even better, well, that's because the theory is wrong. We have been building transportation systems for more than 50 years using the wrong assumptions. We have believed that if we minimize waiting times at stations, we will minimize total travel times, and this is not the case. Living technology can exploit a phenomenon known as lower is faster effect, in which passengers might wait a bit longer at stations, but they will reach their destination faster. Now, if living technology can do this for public transportation, can you imagine what it could do for all of our cities? Our future lies in our hands. It is our decision. We are facing severe urban problems and more will come. But I'm optimistic. Why? Because we have the means to solve all these problems and the ones that will come. Cities will keep on growing. That's a fact. It is our duty to make our cities more livable, but we can do this with living technology. We can live in living cities.