The paper presents the social capital as the essential element of success of the Reggio Emilia preschools known for their unique approach to the early childhood education. The collaborative effort is introduced through examples of the currently ongoing "Reggio Narrates" project of Reggio preschools, the "Dialogue with the Places" and "The Amusement Park for Birds" projects, and ongoing works of the Andersen preschools on "Geography" and "Work of Human Body". What makes Reggio approach truly unique is interdependence between preschools and the city; such a reciprocity is also presented as a defining feature of the social capital concept in opposition to individualism dominating both American and Polish societies. The paper is based on the knowledge acquired during the Dialogues on Education International Study Group organized by the Reggio Children and the Istituzione of the Municipality of Reggio Emilia on April 19-24, 2009 in Reggio Emilia, Italy, and comes from presentation by Antonia Monticelli and Tiziana Filippini, both educators of the Istituzione of the Municipality of Reggio Emilia.