It’s a cautionary tale, a reminder of human messes. It doesn’t focus on how oil is made or what it is used for. It tells how it is pumped from beneath the earth and sent through a pipeline that runs 800 miles through what was once wilderness. It tells how it is pumped onto enormous ships, and how one night the Exxon Valez ran aground and spilled its cargo of oil into the ocean, where it spread for months over thousands of miles of ocean, killing sea birds and otters, and coating shorelines. It tells that thirty years later the place where it happened has never fully recovered.