Natural environments are beneficial for cognitive functioning and affect. Appraisals of such benefits can lead to the development of pro-environmental attitudes and behaviors in the long run. This study aimed to investigate the effects of an indirect exposure to a natural and urban environment during a short break in a school day, using a 'green' video depicting a walk through a lush forest and comparing it to an urban video portraying a walk through a busy city. We involved 91 fourth and fifth graders in a within-participants design. Results show that students decreased their performance in an arithmetic calculation task after watching the urban video, while no significant differences were observed before and after the exposure to the green environment. Students also reported experiencing more negative affect in relation to the exposure to the urban than the natural environment. Moreover, the students perceived the natural environment as more restorative than the urban environment. Taken together, our findings suggest that exposure to urban environments, in contrast to natural environments, may have negative effects on cognitive and affective functioning during school breaks. Educational implications suggest that when it is not possible to stay in a natural environment around the school, or there is no access to nature due to distance, videos of natural environments can be used during short breaks. They have potential to cognitively and affectively benefit students' who may often be exposed to environmental stressors.