On micronations. Sealand, for example.
On forests.
On New York's compost project.
On LAND-I archicolture, a group of architects and landscape architects which deals with landscape at various levels: landscape planning, landscape and environmental design, and mainly focuses on contemporary garden design.
On UNESCO's Heritage Image Archives Initiative, a growing database of high-quality still and moving images of all UNESCO World Heritage Sites.
On sounds like public space.