Wildlife crossings provide crucial routes for animals across the globe

When man-made structures like highways and train tracks block animals' paths, they have a consequential decision to make: Do they try to cross and risk getting hit? Or are they forced to stay in their location, away from access to food and environments they need to survive? For decades, ecologists across the globe have argued that wildlife crossings are crucial in eliminating this dilemma. The World's Bianca Hillier looks into the history of these crossing structures and how they're increasingly necessary today.