A Philadelphia police officer demonstrates a body-worn camera being used as part of a pilot project last December. Matt Rourke/AP hide caption

An example of a human precision grip — grasping a first metacarpal from the thumb of a specimen of Australopithecus africanus that's thought to be 2 to 3 million years old. T.L. Kivell & M. Skinner hide caption

Cherif Kouachi, one of the brothers responsible for the Charlie Hebdo attacks, spent 20 months in Fleury-Merogis prison just outside Paris, where he crossed paths with a radical imam with ties to Osama bin Laden.This photo shows the men's building in May 2014. Charles Platiau/Reuters/Landov hide caption

Family Dollar shareholders agreed Thursday to sell the company to rival chain, Dollar Tree for $8.7 billion. Family Dollar turned down a bigger offer from Dollar General due to antitrust concerns. Joe Raedle/Getty Images hide caption

Jennifer Steinhauer's version of the Sno Ball moves the marshmallow inside and skips the pink food coloring. James Ransom/Courtesy of Clarkson Potter, a division of Random House LLC hide caption

Anti-abortion activists participate in the annual "March for Life" in Washington, D.C., on Thursday. Alex Wong/Getty Images hide caption

French soldiers stand guard in front of the entrance of a synagogue in Lille, northern France, earlier this month. Philippe Huguen/AFP/Getty Images hide caption

The documentary Red Army profiles Viacheslav "Slava" Fetisov — one of the most decorated athletes in Soviet history. Slava Fetisov/Slava Fetisov/Sony Pictures Classics hide caption

Saudi King Abdullah bin Abdulaziz al-Saud is seen in September 2011. Ahmed Abdelrahman/AFP/Getty Images hide caption