The difficulty that secondary education students have with Mathematics and Sciences is a widespread problem in Europe as stated by several international comparative studies like PISA or TIMMS. This scares away these students from following a technical academic path like Engineering. And even when they do so, they still face a lot of problems on these disciplines at the Higher Education level, which generally demotivates them. This is not due to lesser skills of these students but mostly due to wrong educational strategies. We cannot forget that this generation is the "net-generation" or "digital natives": they are surrounded by technology, absorb information in shorter chunks, expect instant responses and feedback and want to be active in their learning. Problem-based learning (PBL) is an active, learner-centred educational pedagogy in which students develop their ability going through a problem solving process, usually based on real-life situations. In a convergent path, games and simulations can be instantiated for learning as they involve mental and physical stimulation and develop practical skills – they force the player to decide, to choose, to define priorities, to solve problems, etc. Engineering is one of the areas where PBL reportedly benefits students with considerable improvements in critical, lateral and creative thinking, problem solving skills, group collaboration and communication skills. The main objective of the eCITY project is to design, develop and validate an online, collaborative, city-development simulation platform (Simcity like) which integrates and exploits Problem Based Learning challenges to be used to scaffold learning in engineering schools and, at the same time, foster the interest in Math, Sciences and Engineering in secondary school students. The older students will tutor the younger ones in the problem solving process. The project will directly reach about 1.000 individuals from the different countries involved.