The U.S. highway system is one of the world’s most efficient transportation networks—for humans. For animals? It’s a concrete jungle that can threaten their very survival. The legendary Highway 101, for example, has long divided and disrupted the mountain lion community in Southern California. But a new wildlife crossing could help reconnect­—and rewild—the fragmented ecosystem. Slated to debut in 2025, the purpose-built walkway will traverse the busy 10-lane highway, offering safe crossing for the area’s animals. And it will also serve as a habitat in itself: High walls of vegetation will buffer traffic noise, while providing a natural home for flora and fauna amid the urban sprawl. Building what will rank as the world’s largest wildlife crossing has meant pulling in an array of partners, including the annenbergfdn, the California Wildlife Conservation Board and nationalwildlife. And project leaders had to navigate extensive environmental reviews as well as fundraising challenges....