among the mega-events is the necessity of delivering a large number of projects from different sectors (e.g., buildings, communication plans, ICT, infrastructure, etc.) The preparation of mega-events like Olympic Games, music festivals, or world expositions requires the successful and timely delivering of many correlated projects: buildings, ICT infrastructure, marketing projects, etc. The international market is increasingly characterized by large and mega-events. The size of these events escalates the complexity of management, often causing budget overruns and scope reduction. As a consequence it is fundamental to effectively monitor the progress of the entire program to react in case the progress does not follow the expected baseline. Project-controlling methodologies are well analyzed in the literature with respect to individual projects. For that which concerns the overall delivery of correlated projects (i.e., a program) the literature provides strategic and operational guidelines; however, far too little attention has been paid to developing quantitative methodology to control their execution phase. The purpose of this article is to review recent research into event planning and program management to propose a quantitative approach, based on the Petri nets and dynamic systems, to obtain the project envelope, a fundamental tool to assess and manage the progress of a program. The methodology is implemented on a real case study: EXPO 2015.