Well-designed and maintained green spaces in cities such as parks, community gardens and tree-lined streets lower the rate of violent crimes, make communities safer and keep people healthier, concluded Cornell University and University of Virginia researchers that conducted a meta-study of 45 papers studying the links between greenery and crime. In particular, more green spaces, such as community gardens converted from vacant lots, decrease gun violence, six studies found. But poorly designed green space with inadequate maintenance, bad lighting and excessive nearby traffic can help crime take root and spread.