Places like nightclubs, festivals, and sports events are commercial sites where people experience atmospheres as shared emotional experiences. Recent research has explained how such atmospheres are formed in interaction ritual chains – ordered sequences of social interactions through which emotions, symbols, and identities are shared and strengthened. With ethnographic data from Liverpool Football Club's Anfield Stadium, this chapter shows that intense atmospheres tend to be formed within 'dense' ritual chains. It extends prior theorisations of how atmospheres are created, by explaining that dense interaction ritual chains are spatially and temporally concentrated social interactions. These allow atmospheres to intensify rather than dissipate by facilitating flows of emotions and symbols between places that constitute interaction ritual chains. In so doing, the chapter reveals the role of temporal and spatial micro-foundations of atmosphere and suggests future research opportunities to understand how different degrees of density might produce different qualities of atmosphere.