sustentabilidad   The concept of sustainability today is really challenged , an item or concept that we as an architects or engineers have to keep in mind for future projects, the meaning of the Sustainability in ecology the word describes how biological systems remain diverse and productive over time. Long-lived and healthy wetlands and forests are examples of sustainable biological systems. For humans, sustainability is the potential for long-term maintenance of well being, which has ecological, economic, political and cultural dimensions. Sustainability requires the reconciliation of environmental, social equity and economic demands – also referred to as the “three pillars” of sustainability. Today everyone is talking about the protection of the environment and how to use renewable energy to otherwise , but what we are really doing is increasing the economic cost of constructions and buildings, Toyo Ito mentioned in one of his books ” Tarzan average in the media Forest ” the goal is not to inject more technology to buildings, rather we have to find a way to preserve the environment, returning  to the most natural construction, in the end return to our principles where we shared the land with nature . The objective is to find a middle ground where we can coexist , with the increasing population and specially with interest in the world to master resources , land and even the countries themselves, the economy in the architecture becomes more complicated because in the end as an architects and as a business, we bow most of the time on the economic side rather than on the environment , comfort and especially the culture, we need to build based on our surroundings , respecting the cultures of each population because we are loosing them. After all the idea to separate buildings from the  infrastructure is not an option because it is a set , and finally the emergence of cities comes from a number of factors that cause its good performance, but instead you can work or create new designs based on the needs of cities, the environment and cultures . Its normal that people tend to believe that what is financially profitable (for developers) is not actually equivalent to economically feasible , because this is due to those same interests that I mentioned, For the people Architects are like those who want to just take advantage needs in order to get more capital. Really in ourselves and future generations is where the change is, to build cities , buildings that meet all human needs , including the cultures of each population and in turn creating a symbiosis with nature or environment , where both parties can benefit and requiring each other . It is a thought that has to start developing and admit that it is very complicated, because society today is tied to the huge economic interests that didnt allow us to change to the next level , for example in class we talked about oil, its development and its lifetime , as well as other resources; where he said that it was going to come a time when those resources would be priceless , would be the point where no one would buy or consume , but  i think in the end there will always be consumers of those resources because the market is made ​​in order to benefit certain people, for example is amazing that now scientists and researchers have generated alternative resources , such as different gasoline, to reduce costs and pollution but is not carried market due the interests of the big  countries have on the other resource (Oil), obviously is not profitable to sell green energy and of course is the same with other resources. The question is how to make a radical change in this regard ? how we can eliminate those interests known to have been throughout history? As much as one may think  is almost impossible , but if anyone can change that , especially in the construction are we as engineers and architects. i think that one of those arquitects that is making his revolution with his new ideas is the Architect Toyo Ito. As we can see in the next picture, shows how only a few people moves the world based in his own interests. Grandes intereses V.S Simbiosis