Events are an important driver of tourism, and occupy an important place in the development and marketing plans of most destinations or tourist boards that promote them. The roles and effects of events in tourism are increasingly important for the competitiveness of a destination. This paper will discuss the nature, evolution and future development of event tourism and will provide basic definitions and definitions of this form of tourism based on theoretical assumptions. In manifestation tourism and promotion in general, the tourist board has a big role. As the paper will give an example of Advent in Zagreb as a large event that has been held in the city of Zagreb for several years in a row, the work will emphasize the role of the Zagreb Tourist Board in promoting this event and its role in strengthening the image of the destination in general. Tourist boards have an important role to play in promoting destinations and coordinating the work of tourism companies in the private sector, such as accommodation facilities and tourist attractions. Advent in Zagreb is an event that has been awarded for three years in a row as the best Advent in Europe and as such has set a high ranking for other events. Advent in Zagreb provides a wide range of content to tourists and takes place in several locations, which will be presented in this paper. Also, as we have been hit by the COVID-19 virus pandemic since 2020, Advent itself has taken a different organizational form and how this pandemic affected Advent itself and the tourism of the city of Zagreb in general will also be explained in more detail in this paper.