A female Marine prepares to throw a practice grenade during Marine Combat Training (MCT) on February 21, 2013 at Camp Lejeune, North Carolina. Since 1988 all non-infantry enlisted male Marines have been required to complete 29 days of basic combat skills training at MCT after graduating from boot camp. MCT has been required for all enlisted female Marines since 1997. About six percent of enlisted Marines are female. (Photo by Scott Olson)

Spencer Slate, costumed as a scuba-diving Easter bunny, is shown in this handout photo provided by the Florida Keys News Bureau as he hides eggs amid eel grass, in the Florida Keys National Marine Sanctuary off Key Largo, Florida March 31, 2013. About 80 adults and children participated in an Underwater Easter Egg Hunt, seeking real hard-boiled eggs painted with non-toxic food coloring to avoid adverse effects on the marine ecosystem. (Photo by Bob Care/Reuters/Florida Keys News Bureau)

Kirby Chambliss of the United States flies in formation with Matt Hall of Australia, Yoshihide Muroya of Japan and Nigel Lamb of Britain prior to the third stage of the Red Bull Air Race World Championship in front of the Petronas Towers in Kuala Lumpur, Malaysia, on May 15, 2014. (Photo by Joerg Mitter/Red Bull via Reuters)

Large trumpet vines spread across electrical lines next to a highway in Kinston, N.C., on June 23, 2014. (Photo by Janet S. Carter/Kinston Free Press via AP Photo)

A picture taken on July 14, 2014 from a Boeing C135 refueling tanker shows two French Rafale fighter planes, flying over the French capital during the annual Bastille Day military parade on the Champs-Elysees in Paris. France has issued an unprecedented invitation to all 72 countries involved in World War I to take part in its annual Bastille Day military parade. (Photo by Franck Pennant/AFP Photo)

Miniature spring-wound 35-mm film camera in a modified cigarette pack. The Tessina’s small size and quiet operation provided more options for concealment than most commercially available models. (Photo by Central Intelligence Agency)

Jill Olsen (R) has her picture taken inside a giant cocoon, from the “Falling Skies” TV series, during the 2014 Comic-Con International Convention in San Diego, California July 24, 2014. (Photo by Sandy Huffaker/Reuters)

Humanoid robot bartender “Carl” interacts with guests at the Robots Bar and Lounge in the eastern German town of Ilmenau, July 26, 2013. “Carl”, developed and built by mechatronics engineer Ben Schaefer who runs a company for humanoid robots, prepares spirits for the mixing of cocktails and is able to interact with customers in small conversations. (Photo by Fabrizio Bensch/Reuters)