An investigator inspects the area near a surveillance camera on the roof of the Lord & Taylor store near the Boston Marathon finish line on Thursday. That camera provided the first glimpse of the men who allegedly planted the bombs. Julio Cortez/AP hide caption

This image from the Federal Bureau of Investigation shows the remains of a pressure cooker that the FBI says was part of one of the bombs that exploded during the Boston Marathon. AP via FBI hide caption

Miguel Modestino, a Ph.D. student at the University of California, Berkeley, is part of the team working to create a solar fuels generator at the Joint Center for Artificial Photosynthesis. Roy Kaltschmidt/Lawrence Berkeley National Lab hide caption

Humberto Manzano Jr. moves a pallet of goods at an Amazon.com fulfillment center in Phoenix in 2010. Amazon has endorsed a bill making its way through the Senate that would require more online retailers to collect sales tax. Ross D. Franklin/AP hide caption

Eric Schmidt, the executive chairman of Google (third from left), and former New Mexico Gov. Bill Richardson (second from right) watch as a North Korean student surfs the Internet. Schmidt and Richardson visited this computer lab during a tour of Kim Il Sung University in Pyongyang, North Korea, in January. David Guttenfelder/AP hide caption

Young people wait in line to enter the Coalition for Humane Immigrant Rights of Los Angeles office on the first day of the Deferred Action for Childhood Arrivals program in August. Frederic J. Brown/AFP/Getty Images hide caption

French jockey Olivier Peslier celebrates a win at Longchamps racecourse near Paris in 2012. While many drugs can legally be used on horses in U.S. racing, they are barred in Europe. Fred Dufour /AFP/Getty Images hide caption