People exercise along the Reflecting Pool on the National Mall in Washington, D.C.; the metro area was ranked as America's fittest city for the second year in a row. Andrew Harnik/The Washington Times/Landov hide caption

itoggle caption Andrew Harnik/The Washington Times/Landov

Sam Swiller and his dog, Sully, in their home in Washington, D.C. Meredith Rizzo/NPR hide caption

itoggle caption Meredith Rizzo/NPR
Corbis

Psyched that it's finally spring? Shifts in the season may affect more than your mood. Corbis hide caption

itoggle caption Corbis

Workers try to remove some of the 11 million gallons of oil spilled by the Exxon Valdez off Alaska in 1989. The ship's third mate may have been up for 18 hours before the accident. Rob Stapleton/AP hide caption

itoggle caption Rob Stapleton/AP

If the Food and Drug Administration has approved a type of prescription contraception, then insurers must cover at least one option at no cost to the consumer. BSIP/Science Source hide caption

itoggle caption BSIP/Science Source
Keith Negley for NPR