When the Wallis-Annenberg Wildlife Crossing opens in December, it will be the largest of its kind in the world. | Dean Musgrove/Los Angeles Daily News In 2012, Southern California was besotted with an unlikely celebrity: a telegenic mountain lion who had crossed one of the state’s most perilous freeways, seeking a territory to call his own. Widely deemed “LA’s loneliest lion” and “most eligible bachelor,” the chiseled puma in question, named P-22, roamed the bustling but otherwise big cat-less Hollywood Hills, unable to safely return to the home he’d left behind. His search for a mate...