The blokhuispoort, a former prison set just inside the old city centre of Leeuwarden, is in urgent need of a significant change. The position of Capital of Culture (ECOC) that Leeuwarden will fulfil in 2018, brings opportunities to regenerate the blokhuispoort and the direct surroundings. Hitherto, studies exist about the intangible impact of the position of ECoC on a city, but no research has been conducted yet on the tangible impact of such an event. To understand the opportunities and analyse what the right strategies are for the physical interventions of future ECOC cities, I have determined a literature study and a selection of case studies. The literature study examines both the importance of temporary use in city planning and the impact of the Event ECOC. The Case study has been performed to obtain insight in the physical interventions catalysed by ECOC. In this way it is possible to understand which characteristics of the intervention regenerate and leave a lasting legacy in the built environment. This case study covers 75 interventions from different ECOC cities. Moreover, five projects are explored even more detailed to strengthen the conclusions out of the case study research.from the case study can be concluded that ECOC can function as the catalyst for the progress of a city and in particular for a specific site in need of regeneration. The actors of this change need to have a clear vision of the city that they are modifying to understand what a specific intervention can mean for the long-term improvement. There are different ways to intervene in the built environment; firstly, an addition to the building stock (temporary or permanently) and secondly, adaption of an existing complex (either renovation or restoration). Out of these four categories aesthetic, functional, and technical characteristics are determined. The functional characteristics include an approachable, flexible and multi-layered programme. Technical characteristics focus on the visual and direct connections with the surroundings, the physical approachability, the innovative construction, program and appearance of the complex. finally, the aesthetical aspects include the iconic design, the ability to identify the intervention. The accomplishment of reaching the community engagement (both neighbourhood, surrounding city and on a larger scale) by taking these characteristics into account, enables the regeneration of the built environment with a long term improvement. This improvement will contribute to the long-term vision and process of cities to become attractive, innovative and with an own identity.