Developing complex systems with a multitude of models requires Global Model Management (GMM) to ensure that the interplay between the models is managed properly, in addition to the activities on each individual model. Such management has to cover the integration of modeling languages, the coordination of all activities on these models, as well as governing all the models and related activities accordingly. While several approaches try to tackle this problem, a solid understanding of the underlying needs and challenges is currently lacking and so far only ad hoc solutions for fragments of the problem exist. Furthermore, most of these solutions will not scale for large models due to their lack of modularity and incrementality. In this modular and incremental Global Model Management project, we therefore want to address the challenges of global model management by means of megamodels with integration links, integration views, traceability links, model consistency, and model operations studying in particular the concepts required to achieve a modular and incremental solution.