New Orleans, Louisiana, July 24, 2008—Oil floats on the Mississippi River after a tanker crashed into a barge carrying industrial fuel oil, causing the barge to spill 419,000 gallons (1,600,000 liters).

Dozens of waterfowl have been found coated in oil, and the slick could contaminate wetlands downstream, officials warned.

Perhaps the biggest impact is economic: The Mississippi is the busiest inland waterway in the United States, and a hundred-mile (161-kilometer) stretch has been closed to nearly all ships since the spill.

• More Photos in the News
• Today's Top 15 Most Popular Stories
• Free Email Newsletter: "Focus on Photography"