Marines finish a 10 kilometer training hike carrying 55 pound (25 kg) packs during Marine Combat Training (MCT) on February 22, 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/AFP Photo)

Indian onlookers stand near the collapsed portion of the flyover in Kolkata on March 3, 2013. A huge portion of a flyover on the eastern side of the Indian metropolis collapsed leaving three persons injured, the flyover connects the airport with Eastern Metropolitan Bypass and the eastern and southern suburbs. As the debris fell into a canal running below the flyover, it took down a truck the driver and two others were rescued from the canal by fire-brigade personnel and locals. (Photo by Dibyangshu Sarkar/AFP Photo)

Lindsay Knutson plays in the heavy snow with her family dog, Aspen, and daughter Flora Bejblik, 4, cq, as her husband Bob Bejblik, rear left, shovels, Tuesday, March 5, 2013 in southwest Minneapolis. The National Weather Service predicted a two-day snow total of 8 to 12 inches for much of southeastern and east-central Minnesota, including the Twin Cities. (Photo by Elizabeth Flores/AP Photo/The Star Tribune)

Smoke rises during an explosion from an Israeli forces strike in Gaza City, Saturday, November 17, 2012. Israel bombarded the Hamas-ruled Gaza Strip with nearly 200 airstrikes early Saturday, the military said, widening a blistering assault on Gaza rocket operations by militants to include the prime minister's headquarters, a police compound and a vast network of smuggling tunnels. (Photo Hatem Moussa/AP Photo)

A visitor stands in front of a portrait taken by artist Bruce Gilden at the “Masters of Photography” exhibition at the Photokina trade fair in Cologne on September 20, 2016. The fair for the photographic and imaging sector, that is running from September 20 to 25, 2016, presents products from image capture, image processing and storage to image output. Photokina also includes a program of events with congresses, workshops, symposiums and photography exhibitions. (Photo by Patrik Stollarz/AFP Photo)

Vehicle lights illuminate a street after a massive blackout, in San Juan, Puerto Rico, Thursday, September 22, 2016. Puerto Ricans faced another night of darkness Thursday as crews slowly restored electricity a day after a fire at a power plant caused the aging utility grid to fail and blacked out the entire island. (Photo by Carlos Giusti/AP Photo)

A woman eats and struggles with her umbrella against powerful gusts of wind generated by typhoon Megi across the the island in Taipei, Taiwan, Tuesday, September 27, 2016. Schools and offices have been closed on Taiwan and people in dangerous areas have been evacuated as a large typhoon with 162 kilometers (100 miles) per-hour winds approaches the island. (Photo by Chiang Ying-ying/AP Photo)

This April 30, 2016 image made available by NOAA shows a deep sea anglerfish living between pillow basalt rock formations, during a deepwater exploration of the Marianas Trench Marine National Monument area in the Pacific Ocean near Guam and Saipan. The ambush predator waits for prey to be attracted by its lure, located between its eyes, and gulps it with its large mouth. (Photo by NOAA Office of Ocean Exploration and Research via AP Photo)