21 Make it desirable Desire is a powerful mobilizer – sometimes stronger than duty or responsibility. If products and buildings that reduce the material cost of building are desirable, they are more likely to catch on with a wider public. Adding beauty, convenience, or novelty to a project can help transform sustainability from something that subtracts to something that adds. The food industry provides a reference for how to tap into the force of desire. People are willing to pay a higher price for a sustainable, organic, pesticide-free tomato not only because it is more sustainable but because it tastes better. Science and technology may develop new, very efficient, low-carbon footprint materials but unless they are cheaper, faster, or easier to use than conventional ones, they are not going to be preferred. In order to promote sustainable materials with the strong force of immediate gratification, we should find a way to make the joy of them more tangible. Image source: LafargeHolcim Foundation. Foregrounding the value of water in Medellín, architects Mario Camargo and Luis Tombé from Colectivo 720 and winners of the Global LafargeHolcim Awards 2015 combine technical and social infrastructure by creating public spaces in a low-income neighborhood.