City , from Latin civitas, is the Urban area that presents a high density of population , made up of inhabitants who they do not usually engage in agricultural activities . The difference between cities and other urban entities is given by population density, legal status or other factors.
It is worth mentioning that there is no precise definition of this term. According to European Statistical Conference of Prague for example a city is a agglomeration of more than 5,000 inhabitants where less than 25% of the population is dedicated to the farming .
Among the main characteristics of cities, there is the predominance of collective and vertical housing (the buildings ), the developed transport and communications infrastructure and the scarce land for green spaces.
The high population density, the high presence of cars and other vehicles and the few green spaces make cities usually present levels of pollution that threaten the Health.
Large cities usually have a financial district, known as city , which houses the main financial institutions and the headquarters of large companies. It is common for these financial districts to receive millions of people who come to to work, and very few people live there permanently.
The metropolitan area of Tokyo , with about 35,000,000 inhabitants, it is considered the largest megacity in the world. Seoul (24.000.000), Mexico (22.000.000), New York (21.800.000), Bombay (21.100.000), Delhi (20,800,000) and São Paulo (20,300,000) are other of the most densely populated cities.
Lilypad, the self-sufficient floating city
He heating, caused by our pollution, and the consequent melting of the glaciers will raise the sea level to a maximum of 90 centimeters throughout the current century. So serious is this situation, that if the temperature rises only one degree centigrade, this could have an increase of one meter in sea level.
What would happen if such an increase occurred? Many regions with high levels of population density would be submerged; some areas of Holland, India and Bangladesh are just three examples of the potential victims of this massive flood. If, instead, the level of sea it would rise two meters, the scope of the catastrophe would be much greater, so much so as to turn New York, Miami, Alexandria and Bombay, among others, into new Venice, with terrible consequences in the economic plane and with a balance greater than 250 million homeless people, who could no longer return to their own, so they would inevitably need to be relocated.
Taking into account these frightening data, a architect of Franco-Belgian origin called Vincent Callebaut devised a floating city, under the name of "Lilypad", which promises to be energy-efficient and self-sufficient. One of its objectives is to expand the territory of countries located on the coasts, a task that some artificial archipelagos currently satisfy; on the other hand, it would serve to give a new home to the millions of climate refugees.
Every Lilypad it would have sufficient capacity to accommodate more than 50 thousand people, and it would be built around a submerged lake, which would supply the Water pluvial. It would lead to the establishment of private homes, offices and even shopping centers; all aboard an island whose course would be decided by wind and sea currents.
On the other hand, three ports would keep it communicated with the rest of the world, and the suspended gardens and orchards that would cover it would allow the cultivation of food, ensuring its inhabitants sufficient resources to spend their lifetime whole
Finally, its name comes from English and refers to water lilies, which would also take its appearance, with a size 250 times larger.