Landscape architecture can be more than aesthetically innovative: it can contribute to integration in society, social stability, and a vibrant public life. But how does a park become an intensively used stage, a well-visited everyday location? What constitutes the "boon of life" (Jane Jacobs)? And what makes a park urban?The Park am Gleisdreieck in Berlin--developed between 2007 and 2014--was initiated by citizens and built in dialogue with them. This publication presents the principles underlying its design. They form a toolbox for big city parks that can be used in diverse ways, stimulate interaction, and appeal to the senses. Furthermore, the book situates the park within the contemporary work of landscape architecture and shows how visitors perceive the park and its atmospheres. Overall, this work lays out the design elements that model a successful citizens' park in the twenty-first century: Many voices have contributed to its development; its design is dynamically complex, and the park invites change and appropriation.