A term for les délaissés (leftover spaces of urban development) for nature to colonise. Coined by Gilles Clément, a French garden designer, botanist, entomologist and writer, in a manifesto entitled ‘Manifeste du Tiers paysage’.
In ‘Manifeste du Tiers paysage’, Clément argues that neglected and unexploited space is a reserve under the term third landscape. Left to evolution, biological processes and agency transform anthropized territories to natural spaces which provide biodiverse habitats for fauna and flora but can also be used by society as spaces for leisure and connection to the natural world.