A Marine Corps F-35B Joint Strike Fighter does a short takeoff (STOVL) from Patuxent River Naval Air Station, Md., in 2011. Eighteen years after development began, a version of the plane designed for the Marine Corps is expected to be deemed "combat ready." Cliff Owen/AP hide caption
The Japanese supercomputer K, pictured in June 2012 at the RIKEN Advanced Institute for Computational Science in Kobe, western Japan. The K computer is currently ranked No. 3 on a list of the 500 fastest supercomputers. Kyodo/Landov hide caption
Secretary of State Hillary Clinton testifies in January 2013 before the Senate Foreign Relations Committee on the attack on the U.S. mission in Benghazi, Libya. Mandel Ngan/AFP/Getty Images hide caption
Zachary Gallegos, 23, stands guard outside the Armed Services Recruiting Center on Thursday in Sioux Falls, South Dakota. The Pentagon has asked such self-appointed "armed citizens" to leave, citing security concerns. Kevin Burbach/AP hide caption
An elephant in South African offers an up-close glimpse of its prodigious instrument. According to Sean Hensman of Adventures with Elephants, trunks like this one could help the U.S. Army develop a better landmine sensor. Greatstock/Barcroft Media/Barcroft Media/Landov hide caption
President Obama is hugged by his half-sister, Auma Obama, accompanied by Kenya's President Uhuru Kenyatta (right) as he arrives at the Jomo Kenyatta International Airport in Nairobi on Friday. Ben Curtis/AP hide caption
A U.S. Air Force plane takes off as a Turkish air force fighter jet taxis at the Incirlik airbase, southern Turkey, in 2013. Reversing an earlier policy, Ankara has agreed to allow the U.S.-led coalition to fly anti-ISIS airstrikes from the base. Vadim Ghirda/AP hide caption