The main ring of the Tevatron, seen in a time exposure. For a quarter century, the particle accelerator at a lab outside Chicago was the most powerful machine of its kind in the world. Reidar Hahn/Fermilab hide caption

itoggle caption Reidar Hahn/Fermilab

Kansas Secretary of State Kris Kobach says the Sept. 11, 2001, terrorist attacks energized him around the issue of illegal immigration. "We discovered that five of the 19 hijackers had been in the country illegally," Kobach says. Ed Zurga/AP hide caption

itoggle caption Ed Zurga/AP

Ryan Witmer (left) and Jhonmar Castillo wait with other couples to exchange vows in a civil union ceremony June 2 in Chicago's Millennium Park. New data from the U.S. census may reveal as much about changing attitudes as about changing numbers. Scott Olson/Getty Images hide caption

itoggle caption Scott Olson/Getty Images

Officials from Arizona-based First Solar and a New Mexico power company gather after the dedication of a new solar array in Albuquerque in April. Susan Montoya Bryan/AP hide caption

itoggle caption Susan Montoya Bryan/AP