From guerrilla gardeners who transform urban blight into delightful gardens, to major redevelopment projects that reshape the relationship between people and the urban landscape, to community gardens tended by pensioners or prison gardens dug by inmates. These are just a few of the examples of the greening of cities: rarely part of a precise political agenda of local governments, which continue to ignore the issue, more often linked to small group initiatives or individuals who live in contact with nature as part of their civil rights and as an expression of a basic need.