The Exxon Baton Rouge, smaller ship, attempts to off load crude oil from the Exxon Valdez in Prince William Sound, Alaska on March 26, 1989. The ship ran aground spilling more than 270,000 barrels of crude oil. Experts call it the United State's worst oil spill ever. (AP)

Photos: The Exxon Valdez spill

It was 25 years ago the Exxon Valdez spilled more than 10 million gallons of crude oil in Prince William Sound, Alaska.