Surrounded by barren cities, sterile concrete or over maintained, uniform patches of green, more and more animals are losing their last places of retreat. The city continues to grow inexorably but, where humans fail to impose their order, nature sprouts and crawls out of the tiny cracks in the asphalt and concrete and re-conquers its territory. Disused land is often the last place of retreat for wild animals in the city. More than two thousand species of plants can be found in Vienna alone, as well as half of all Austrian breeding birds and two thirds of the country's mammals. Many disused areas in Vienna are home to a host of threatened species like, for example, crested larks, nightingales, praying mantisses or firebellied toads. Countless mammals, birds, insects and amphibians are making their homes here once again. The city's wilderness is characterised by their comings and goings, their struggle to survive and their quest to find increasingly scarce resources and habitats.