Computer games represent a vast economic market, a key driver of technology, and an increasingly powerful medium for a broad range of applications. The latest wave of innovation for computer games is 'mobile' and, more precisely, 'location-based'. These outdoors mobile experiences are radically different from traditional computer games or their mobile equivalent. They focus the players' attention on the real world around them as much as on the digital world of the game, aiming to create a powerful juxtaposition of the two.Although location-based gaming is an industry on the verge of explosive growth, the creation and deployment of such experiences, especially those involving multiple participants, is simply out of reach for the vast majority of creative industries and authors because of the blend of many cutting-edge technologies they require, their hard to master limitations, and the complex gaming concepts they employ.The first objective of MAGELLAN is to deliver an unprecedented authoring environment based on visual authoring principles in order to enable non-programmers, as well as more advanced users, to cost-effectively author and publish multi-participant location-based experiences. The second objective is to deliver a scalable web platform featuring social networking means and supporting the publication, browsing and execution of a massive number of such experiences. Finally, MAGELLAN will produce a series of guides for authors of location-based experiences that will constitute a reference for interested people as well as a foundational document for future research in the field.To achieve this, MAGELLAN will adopt a holistic approach integrating interdisciplinary research involving a complementary group of world-class experts from multiple scientific and technological domains. A user-centred approach will be adopted in order to place end-users, represented by the 5 SMEs partners and the open User Group members, at the heart of the project.