Spending time in green spaces (like parks, forests, and gardens) and blue spaces (such as lakes, rivers, and coastlines) can help prevent disease and improve longevity. Unlike medicines that usually work on just one part of the body, natural spaces help us in many ways at once. Research shows that being in these environments can lower pollution, encourage exercise, help us relax, expose us to helpful microbes, connect us to others, and may even boost our immune system.