Through his evolution, Human being built his own environment, and then superimposed it to the original nature. Now generations were born in this artificial environment and never leave it in their whole lives. Those cities where everything must be under control, including the grass that grows between pavers. Where the horizon cannot be found behind the walls. Where the night is never dark. Where silence is unknown. Where someone must hold the line no matter what.
Human is finally unadapted to his initial nature for another he established by himslef and which wont last after him.
Urban nature is that friction between a specie and a world, an ephemeral order made by chaotic butterflies.