 This paper reviews the existing literature on the relationship between built environments and physical activity among older adults. It finds that certain built environment features are associated with higher levels of physical activity among older adults, such as walkability, safety from crime, access to destinations and services, recreational facilities, parks, public open spaces, greenery and aesthetic scenery, walk-friendly infrastructure, and access to public transportation. These findings suggest that creating more walkable communities and providing safe places for older adults to exercise could help increase their physical activity levels. This article was authored by David W. Barnett, Anthony Barnett, Andrea Nathan, and others.