Mongolia's Olympic wrestler Battsetseg Soronzonbold (front) fights with her training partner during a daily training session at the Mongolia Women’s National Wrestling Team training centre in Bayanzurkh district of Ulaanbaatar, Mongolia, July 1, 2016. Battsetseg Soronzonbold became a national hero in her native Mongolia after winning wrestling bronze at the London Olympics and is determined to turn the medal into gold in Rio next month. (Photo by Jason Lee/Reuters)

A U.S. Marine kneels beside a Multi-Utility Tactical Transport ( MUTT) during a patrol as part of Rim of the Pacific (RIMPAC) 2016 an exercise held at Camp Pendleton, California United States, July 13, 2016. (Photo by Mike Blake/Reuters)

A man dressed in leaves and animals of the forest, the Redeemer on his shoulder, holding the Olympic torch and wearing Olympic rings glasses walks along Copacabana Beach, Rio de Janeiro, Brazil, 31 July 2016. The 2016 Olympic Games start on 05 August. (Photo by Barbara Walton/EPA)

Astronomer, space scientist and meteorologist Andrea Opitz, senior research associate of the Space Physics and Space Technology Department of Hungarian Academy of Sciences (MTA) Wigner Research Centre for Physics (2R) wears a space suit during a cosmology exhibition in Budapest, Hungary, 03 March 2016. The photo series was created to mark the International Women's Day (IWD), which was marked for the first time in 1911 and is celebrated on 08 March since 1913. (Photo by Bea Kallos/EPA)

A boy collects drinking water from a hand pump in Kutubdia, Bangladesh on March 30, 2016. Kutubdia is one of many islands affected by some of the fastest recorded sea-level rises in the world. The island has halved in size in 20 years. (Photo by SIipa/Rex Features/Shutterstock)

In this March 29, 2016 photo, a man shoulders a coffin with the remains of a loved one who was slain more than two decades ago by Shining Path rebels, as he walks to the cemetery for a group burial service, in Ccano, a village in the Huanta area of Ayachcuo department, Peru. Presidential candidate Keiko Fujimori's base of support is in places like Ccano, where promises to build roads, clinics and schools recall her agronomist father’s own legacy of delivering aid to the long-overlooked countryside. (Photo by Rodrigo Abd/AP Photo)

Iraqi Kurdish female fighter Haseba Nauzad looks through a pair of binoculars during a deployment near the frontline of the fight against Islamic State militants in Nawaran near Mosul, Iraq, April 20, 2016. (Photo by Ahmed Jadallah/Reuters)

In this photo taken on Thursday, July 23, 2015 migrants enter a train to Serbia at the railway station in the southern Macedonian town of Gevgelija. The country has become a major transit route for thousands of Middle Eastern and African refugees and migrants who cross over from Greece and then continue into Serbia. (Photo by Boris Grdanoski/AP Photo)