Free movement through large areas is a basic requirement for permanent existence of large mammals. Migrations allow populations of these species to supplement “sink spots”, to balance fluctuations in abundance due to unfavourable conditions on a short-term basis and to maintain sufficient genetic diversity. However, today’s landscape – more and more intensively used by humans – contains increasing numbers of barriers that block free migrations of animals. Such barriers are represented by quickly increasing housing development and most of all by expanding transport infrastructure. If we want to keep conditions allowing the existence of large mammals, it is necessary to delimit existing migration corridors and to ensure their protection. It is crucial to ensure permeability by means of safe fauna passages, either underpasses or overpasses (green bridges). Such constructions are unfortunately very expensive, therefore the requirement to build them has to be always very well justified. Protection of migration corridors in local urban plans is also very important, because an interruption in just one place can mean destruction for the entire corridor.