Research indicates that contact with nature elevates positive emotions; however, relatively less work examines the mechanisms responsible for these effects. The present study experimentally tested whether a brief experience in nature promotes specific positive emotions, such as happiness, joy, and feelings of awe because of feeling absorbed and fully involved in its natural features. Participants (N=100) were randomly assigned to either sit in a natural environment (i.e., a local arboretum) or a built environment (e.g., an outdoor stadium) for 15min while focusing their attention on their surroundings, and afterward rated their current feelings. Results from structural equation modeling analyses indicated an excellent fit for a mediation model in which experience in a natural environment, as opposed to a built setting, significantly enhanced feelings of awe and other positive emotions, chi(2) (22)=22.86, p=.41, CFI=1.00, RMSEA=.02, 90% CI (<.001, .09). Moreover, absorption emerged as a significant mediator of nature's impact on positive emotions. There was a particularly strong effect on feelings of awe (68% of variance explained by the full model). Results indicate that nature fosters awe and other positive emotions when people feel captivated and engrossed in their surroundings. The present study extends research on nature's positive emotional benefits and provides implications for nature-based interventions, specifically on the significance of having absorbing experiences in nature.