This architect is trying to save cougars from becoming roadkill on California freeways

Architect Robert Rock is facing a Herculean task: Design a bridge that will allow mountain lions to cross safely over a stretch of the 101 Freeway that roars with the traffic of 300,000 vehicles each day.

On a recent morning, he stood on a hilltop and gazed at a vista of steep fire-stripped slopes, rocky arroyos, weedy humps and 125-degree grade shifts on both sides of the freeway at Liberty Canyon in the city of Agoura Hills.