Over 20 years ago, on March 24, 1989, an oil tanker crashed into an underwater reef and spilled over 260,000 barrels of crude oil into the Prince William Sound in Alaska.
This event was the most devastating "human-caused" environmental disaster at that point in time.
As oil continued to spill into the water, salmon, sea otters, seals, and birds of all kinds suffered greatly.
These animals were exposed to large amounts of oil and were dying in the thick toxic goo.
This event is known as the Exxon Valdez oil spill.
Here's an interesting letter written from Kelli Middlestead to Walter Stieglitz, the director of the Alaska region of the U.S. Fish and Wildlife Service.