See the most compelling images from the oil spill one year ago.
Mario Tama / Getty Images
Church members read bibles while participating in an early morning prayer vigil to mark the one-year anniversary of the BP oil spill on April 20 in Orange Beach, Alabama. Orange Beach on the Gulf Coast was impacted by oil in the aftermath of the Deepwater Horizon rig explosion which killed eleven crew members. 206 million gallons of oil eventually spilled into the Gulf of Mexico until the BP well was finally sealed. April 20 marks the one-year anniversary of the worst environmental disaster in U.S. history.