It is impossible to walk across San Francisco’s Mission Bay district, a former landfill, without appreciating the waterside parks, grassy lounging areas, and for-rent gardening plots. The numerous spots of green among the sleek concrete and mirrored glass condominiums lend life to the otherwise cold and colorless neighborhood. Green spaces have proved beneficial in almost every measurable way, including benefits for the environment, physical health, and overall wellness. Increasingly, Americans have moved out of small towns and into the cities, with 4 out of 5 Americans living in an urban setting (4). In recent years, nearly all major U.S. cities have seen population growth, but from 2010-2012 the greatest growth was seen in Austin, TX, with an increase of 6.6%; Denver, CO with an increase of 5.7%; and Atlanta, GA, with an increase of 5.7% (4). As these cities and others continue to demonstrate rapid population expansion, it is imperative that the inclusion of green spaces be considered in the correspondingly dense city plan. Quite obviously, the inclusion of greenery in urban settings positively impacts the surrounding environment. Significantly, this occurs in the heat regulation of urban areas. One study in Manchester, UK found a 3-4 ºC decrease in ambient temperature corresponding to a 10% increase in tree canopy (2). Urban greenery may not represent a grand solution for the highly publicized “global warming” issue, but it certainly presents a noticeable remedy for local warming. As the residents of San Francisco, and all of California, would undoubtedly appreciate, urban parks prove invaluable for water regulation. While “impervious” ground cover can lose 40-83% of rainfall due to surface runoff, forested landscapes only lose 13% in similar precipitation events (2). The increasing frequency of global and domestic drought makes this effect quite a tangible value for urban residents, if environmental altruism is not enough in and of itself. Another merit of urban parks comes in the form of habitat maintenance. Initial expansion across the country included little consideration of the possible effects on native species and biodiversity. Urban parks, when developed correctly, contribute to a “mosaic of habitats”(2). Moreover, the addition of urban parks increases the “insurance value” of a city, meaning the city will have an increased ability to respond and adapt in the face of disturbance, like a flood or earthquake (2). The mitigation of physical stresses on an area could prove especially valuable to cities that face the threat of rising oceans. The environmental effects of urban greenery are numerous and beneficial and they present an important argument for the inclusion of green spaces in developing cities. An additional, although less concrete, merit of urban green spaces relates to the physical health of neighborhood members. While urban greenery has not been proven to have any specific influence on major health indicators, it has been generally utilized to prevent health problems such as obesity in high-risk urban populations (3). Although specific health benefits have not yet been proven, health and park usage have a widespread perceived correlation. However, in a medical setting, green spaces– and plant life in general – have been found to have a positive impact on patient recovery. In particular, one study demonstrated that patients recovering from surgery improved more rapidly when exposed to greenery (5). This finding indirectly suggests an influence of parks on the health and wellness of urban individuals. The greatest benefit by far of parks on residents themselves takes the form of overall well-being. The Gallup-Healthways Well-Being Index (WBI) creates a comprehensive assessment of wellness from physical, community, social, financial, and purpose factors (4). In one study, the WBI of individuals in urban areas was found to increase with an increase in park quantity (percentage of city area covered by public parks), as suggested by enhanced physical and community well-being (sense of safety and engagement in the community) (4). While not statistically significant, park quality (per capita spending on parks) also had a positive relationship with well-being. This suggests that even parks of lower quality may have some positive impact on the wellbeing of residents of large cities. Moreover, in one study, individuals enjoying a green area demonstrated lower frustration, attentional engagement, and higher meditation, according to analysis of their brain electrical activity (1). On the whole, individuals with exposure to green spaces tended to display greater emotional and physical well being than individuals who did not frequent green areas. While many of their positive impacts require further confirmation, the overwhelming evidence in support of green spaces in urban settings suggests a need for more of these areas. Whether it takes the form of a tree-lined city street or a public vegetable garden, or whether it is as small as a single-lot garden or as large as San Francisco’s Golden Gate Park, urban greenery can only improve the lives and livelihoods of the residents of America’s largest cities. As we look forward to urban expansion, particularly in those fast-growing cities, such as Austin, Denver, and Atlanta, it is necessary for urban planners and local citizens to advocate for the inclusion of these treasured spaces. When considering that the landscape of a city can last for years, or even decades, it is the responsibility and the honor of those advocates to build a city where current and future residents can both live and flourish. REFERENCES Aspinall P, Mavros P, Coyne R et al. The urban brain: analysing outdoor physical activity with mobile EEG. Br J Sports Med 2015;49:272–6. Gill SE, Handley JF, Ennos a R et al. Adapting cities for climate change: The role of the green infrastructure. Built Environ 2007;33:115–33. Jennings V, Larson L, Yun J. Advancing Sustainability through Urban Green Space: Cultural Ecosystem Services, Equity, and Social Determinants of Health. Int J Env Res Public Heal 2016;13:196. Larson LR, Jennings V, Cloutier SA. Public parks and wellbeing in urban areas of the United States. PLoS One 2016;11, DOI: 10.1371/journal.pone.0153211. Ulrich R. View through a window may influence recovery from surgery. Science (80- ) 1984;224:420–1.