A “Free Syrian Army” fighter in the Bustan Pasha neighborhood of Aleppo, Syria, August 21, 2013. (Photo by James Lawler Duggan)

Indonesian activists covered with sludge from the mud volcano hold a protest during five year anniversary of the Sidoarjo mud eruption on May 29, 2011 in the subdistrict of Porong in Sidoarjo, East Java, Indonesia. (Photo by Ulet Ifansasti/Getty Images)

Members of the public admire trees displaying their autumn colours at the Royal Horticultural Society Garden Wisley on October 26, 2011 in Wisley, England. Many deciduous trees have now changed colour as they begin to shed their leaves for Autumn. An extended period of leaf colour change has come about this year due to a warm, dry Spring prompting an early growth spurt and a premature colour change. (Photo by Oli Scarff/Getty Images)

Veteran racehorse Morestead models the world's first authentic Harris Tweed suit designed for a racing horse, which has been specially commissioned by William Hill to celebrate the opening of this year's Cheltenham Festival on March 15, 2016 in the U.K. (Photo by Joe Pepler/Rex Features/Shutterstock)

A monkey jumps from a branch at Yangon Zoological Gardens in Yangon, Myanmar, 06 April 2016. Yangon Zoological Gardens (Yangon Zoo) is the oldest and second largest zoo in Myanmar. (Photo by Lynn Bo Bo/EPA)

A child sleeps under a table at the Jorkpan market in Sinkor district in Monrovia, Liberia on May 2, 2016. (Photo by Marco Longari/AFP Photo)

The feet of a Filipino penitent is nailed to a wooden cross during Good Friday rituals on April 3, 2015 at Cutud, Pampanga province, northern Philippines. Several Filipino devotees had themselves nailed to crosses Friday to remember Jesus Christ's suffering and death, an annual rite frowned upon by church leaders in this predominantly Roman Catholic country. (Photo by Aaron Favila/AP Photo)

“Double head vulture”. On the day of windy days during raptors migration some people in my country start to catch these tired raptors, so in this day we go to photograph some raptors and we saw these tow tired vultures, so we start to drag them away from the hunters until they reach a good hidden place, to make them safe until they start a new journey. Photo location: Kuwait. (Photo and caption by Mohd Khorshed/National Geographic Photo Contest)