The following study analyzes the Parc de la Trinitat, an urban park that is immersed in one of the most important infrastructures of the city of Barcelona, the road junction located in the northeastern part of the city, the Nus de la Trinitat. As the title indicates, the park also becomes the North Entrance to the city, and the reason for this work. Starting from a constructed reality, we analyze the historical situation that led to its construction, beginning with the events that triggered its conception and design: a claim for the inhabitants of the Trinitat neighborhood. This study is intended as a first approach to future research on barriers in urban space.