Children play on a Nigerian oil-flow station in 2007. Nigeria, a major oil source for the United States, is riddled with ancient pipes and constant spills. That, plus the geopolitical challenges involved, is why much of Nigeria's crude is the kind of "tough oil" that author Michael Klare describes. George Osodi/AP hide caption

Plaquemines Parish coastal zone director P.J. Hahn lifts an oil-covered pelican, which was stuck in oil at Queen Bess Island in Barataria Bay, just off the Gulf of Mexico, in early June. Gerald Herbert/AP Photo hide caption

Frank Loesser won the Academy Award for his song "Baby It's Cold Outside." Stroud/Express/Getty Images hide caption

Women take part in a 1977 demonstration in New York City demanding safe and legal abortions for all women. Peter Keegan/Stringer/Hulton Archive/Getty Images hide caption

Sen. Robert Byrd on Feb. 20, 1963, when he had already spent a decade in Congress. Charles Gorry/AP hide caption

Dan Gottlieb hosts a mental-health call-in radio show on WHYY. In 1979, was in a near-fatal car accident that left him paralyzed from the chest down. hide caption

Kyle Steiner, a member of Battle Company, stands in the Korengal Valley in Afghanistan's Kunar Province. Battle Company's actions were the basis of the documentary Restrepo by Sebastian Junger and Tim Hetherington. Outpost Films hide caption

An image from the BP video shows oil gushing from the blown well in the Gulf of Mexico. AP hide caption

Over four months, ABC News followed doctors, nurse and patients at three hospitals in Boston. ABC hide caption