Pipefitters work on construction of the Keystone XL pipeline's southern portion outside Tulsa, Okla., in January. PR Newswire hide caption

Mississippi state Sen. Chris McDaniel speaks to supporters in Jackson on Thursday. He is challenging Republican Sen. Thad Cochran in Cochran's bid for a seventh term. Rogelio V. Solis/AP hide caption

Atlas V (left); Falcon 9 (right) ULA; SpaceX hide caption

Shoppers gaze at a jewelry store display window in the Turkish capital Ankara on Feb. 19. Some economists have coined the term MINT to include the up-and-coming emerging markets of Mexico, Indonesia, Nigeria and Turkey. But Turkey has been hit by street protests, and others in the group have had their share of recent turbulence. Adem Altan/AFP/Getty Images hide caption

The Vladivostok warship, a Mistral class LHD amphibious vessel ordered by Russia, at the STX France shipyard in Saint-Nazaire, France, on Friday. The Vladivostok is one of two ships Russia ordered from France. Jean-Sebastien Evrard/AFP/Getty Images hide caption

A turnspit dog at work in a wooden cooking wheel in an inn at Newcastle, Carmarthen, Wales, in 1869. Ann Ronan Pictures/Print Collector/Getty Images hide caption

An Israeli places a flower beside the name of the World War II Nazi concentration camp Bergen-Belsen during a ceremony marking Holocaust Remembrance Day at Yad Vashem in Jerusalem, on April 28. The Israeli government is weighing a new plan that would get more financial help to elderly Holocaust survivors, including about 50,000 in the country who are living below the poverty line. Ammar Awad/Reuters/Landov hide caption

Since forming The Black Keys in 2001, Patrick Carney (left) and Dan Auerbach have evolved from a scrappy home-recording aesthetic into something grander. Danny Clinch/Courtesy of the artist hide caption