Animals once had the entire planet at their disposal — one vast, immense reserve in which the only laws in force were those of nature. Then came humans, and natural spaces began to fragment more and more, pushing other species to the margins and severing the connections between different areas.

These connections are vital for certain species that use wide ranges, particularly predators and large mammals, and have been cut off by urbanisation. In an attempt to repair the damage caused, humans have created various ecological corridors around the world — that is, the restoration of interconnected habitats that allow the movement of wildlife and genetic exchange between plant species. Here are some of the most effective "nature motorways".

1. Terai Arc Landscape

The Terai Arc Landscape (Tal), born from a collaboration between the Wwf and the Nepalese government, is a narrow subtropical corridor between India and Nepal that crosses eleven protected areas. Grasslands, forests and river valleys are home to rare and threatened species, such as the Asian elephant (Elephas maximus), the Indian rhinoceros (Rhinoceros unicornis) and the Bengal tiger (Panthera tigris tigris).

2. Banff Wildlife Bridges

In Banff National Park, in Canada, there are some remarkable bridges built specifically for animals. The crossings, between 10 and 60 metres wide and covered with local vegetation, are designed to encourage animals such as deer, elk and bears to use the bridges rather than cross the busy Trans-Canada Highway. To date, naturalists have documented more than 140,000 animals crossing the road using the bridges or underpasses.

3. Christmas Island, bridges and tunnels for crabs

Not all corridors have been designed for large mammals. On Christmas Island, in Australia, the spectacular migration of red crabs (Gecarcoidea natalis) takes place every year. The crustaceans live in the island's forests, but every year they migrate en masse towards the ocean to breed and lay their eggs. To protect the crabs from being crushed by vehicles, park staff have built bridges and tunnels.

4. Oslo, Bee Highway

Norway's is the world's first "motorway" designed exclusively for bees. Oslo does not have enough urban parks, and therefore also lacks the plants that pollinators such as bees need to survive and thrive. All citizens are invited to contribute by sowing flowers and plants and building insect hotels, so as to provide pollinators with food and shelter along the city's main arteries.

5. The European Green Belt

This wild strip of nature stretches more than 8,500 kilometres, from Finland to Greece. The idea for the European Green Belt was born in Germany, shortly after the fall of the Berlin Wall. The corridor lies where the Iron Curtain once stood, so in addition to protecting wildlife it carries a historical and cultural significance. This area, cleared of barbed wire, floodlights and landmines, represents today an invaluable ecological backbone, made up of forests and nature parks, connecting the Baltic to the Adriatic.