Japan Self-Defense Force officers in radiation protection suits hold a blue sheet over patients who were exposed to high levels of radiation at the Fukushima Dai-ichi nuclear power plant on March 25. A team of experts at Japan's National Institute of Radiological Sciences have helped treat injured workers. Jiji Press/AFP/Getty Images hide caption

itoggle caption Jiji Press/AFP/Getty Images

This shipping container was discovered upside down on the seafloor by researchers in June 2004, four months after it was lost at sea. Monterey Bay Aquarium Research Institute hide caption

itoggle caption Monterey Bay Aquarium Research Institute

Steve Jobs and Steve Wozniak formed Apple Computer Co. on April Fool's Day, 1976. The Apple I, introduced soon after, was the first computer to come with a fully assembled motherboard (central printed circuit board). It sold for $666.66. Science & Society Picture Library / Contributor/Life hide caption

itoggle caption Science & Society Picture Library / Contributor/Life

Cows that consume feed, grass or water contaminated with radioactive iodine-131 can concentrate the element in their milk. Peter Elvidge/iStockphoto.com hide caption

itoggle caption Peter Elvidge/iStockphoto.com

A view of the Three Mile Island power plant near Harrisburg, Pa., site of the worst nuclear accident in U.S. history. In 1979, a reactor at the plant experienced a partial meltdown, but radioactive material never escaped containment. Bradley Bower/AP Photo hide caption

itoggle caption Bradley Bower/AP Photo

The facilities at the Fukushima Dai-ichi nuclear power plant were designed to withstand strong earthquakes and tsunamis, but not to the strength and size experienced on March 11. Air Photo Service/AP hide caption

itoggle caption Air Photo Service/AP