On April 29, 1975, as Saigon was falling to Communist North Vietnamese forces, a small U.S. Navy destroyer escort ship, the USS Kirk, played a dramatic but almost forgotten role in rescuing up to 30,000 South Vietnamese. Here, a member of the USS Kirk's crew tends to a Vietnamese baby. Hugh Doyle hide caption
Villagers displaced from their homes walk through flood waters on August 24, 2010, near Muzaffargarh in Punjab, Pakistan. Daniel Berehulak/Getty Images hide caption
The Ebola virus causes a hemorrhagic fever that is usually deadly. Frederick Murphy/CDC hide caption
Why don't Tibetans feel lightheaded this high above sea level? It's in the genes. iStockphoto.com hide caption
Canadian Prime Minister Stephen Harper (left) and French President Nicolas Sarkozy meet at the G8 summit in Huntsville, Ontario. Eric Feferberg/AFP/Getty Images hide caption