Someone can correct me ? :) How technology can help cities deal with their issue ? Today, 54% of world population lives in urban centers. By 2050, this proportion will increase up to 70%. Because of their high density of population and infrastructure, the cities have a very important impact on the environment, they consume almost two-third of the energy... We must find solutions to deal with its issue. Despite this issues, the cities contribute at the worldwide economy. 30% of the global economy is concentrate in just 100 cities. Technology can be the solution to help the cities to deal with their issue. A smart city is a city which is equipped in infrastructure, digital technologies or information and communication technologies which are in order to improve the quality and the performance of the urban services, to decrease costs and resource consumption, and to engage more effectively with its inhabitants. The different infrastructure assure water and electricity supply, a waste management, an efficient urban mobility and public transport... The smart cities aim to promote adoption of smart solutions to use more efficiently the different assets, resources and infrastructures available. The city of Santander in Spain is one of the most famous Smart Cities in the world. The city has created a very important network. In the city we can found 12.000 sensors and network infrastructure to continually measure air quality, weather, traffic and a lot of other parameters. The various sensors are used in different sector. They are useful for drivers. To help driver and to reduce emissions from cars, 400 sensors are present in public parking lot to track open parking spots. They are also use for environment. In effect, more than 2.000 sensors measure noise, light, carbon in the air, to help the city to obey regulations on noise and air quality. Sensors enable to build a sound map to help the city comply with European Union noise regulations. The different sensors are also located in lampposts in parks sense pedestrians and reduce light when there is nobody around. Sensors are also use to control the traffic. There are sensors under the pavement at the city's entrance, tracking traffic volume and location, and the speed of cars. We can see, trough the example of the city of Santander, that the technologies can help the cities to deal with their issue.