It's 25 years since the Exxon Valdez oil spill; six years since "Drill, baby, drill," and four years since the start of the BP oil spill in the Gulf of Mexico. Now, thanks in part to the oil patch in North Dakota, the United States has become the world's biggest producer of oil and gas.
We take the Exxon Valdez anniversary as an opportunity to look at the state of oil drilling in America. How have events in the last quarter-century changed the U.S. oil game? And what have new technologies allowed us to accomplish?