Above the whirring of 300,000 cars each day on Los Angeles’s 101 freeway, an ambitious project is taking shape. The Wallis Annenberg wildlife crossing is the largest wildlife bridge in the world at 210ft long and 174ft wide, and this week it’s had help taking shape: soil. “This is the soul of the project,” says Beth Pratt, regional executive director, California, at the National Wildlife Federation, who has worked on making the crossing become a reality over the last 13 years. She says she’s seen many milestones, like the 26m pounds of concrete poured to create the structure, but this