U.S. Army helicopters providing support for U.S. ground troops fly into a staging area fifty miles northeast of Saigon, Vietnam, August 28, 1966. Helicopter fuel is stored in the large rubber tanks, foreground. (Photo by Henri Huet/AP Photo)

A couple dances a tango in front of Saint Peter's basilica at the Vatican, December 17, 2014. At the rear edge of the square more than 2,000 people, who came to Rome from all over Italy for the 78th birthday of Pope Francis, danced in “A tango for Pope Francis” event as music blared. (Photo by Tony Gentile/Reuters)

A performer from Cirque du Soleil's show “Quidam” practices backstage before a show at the MEO Arena in Lisbon December 18, 2014. (Photo by Rafael Marchante/Reuters)

People take pictures and Buddhist monk chants as a groom and a bride lay inside a pink coffin during their wedding ceremony at Wat Takien temple in Nonthaburi province, on the outskirts of Bangkok February 14, 2015. Ten Thai couples laid in the pink coffin starting 9:09 AM on Saturday during the wedding ceremony organised by the Buddhist temple on Valentine's Day. Couples believe laying briefly in the coffin will get rid of bad luck and usher happiness into their lives. (Photo by Damir Sagolj/Reuters)

In this Saturday, March 21, 2015 photo, a porter rests carrying supplies for the upcoming climbing season, near the Everest Base camp, Nepal. Nepal has cleared more than 300 mountaineers to climb Mount Everest after they had to abandon last year's efforts when an ice avalanche killed 16 guides in the mountain's deadliest disaster, an official said on March 20. The three-month climbing season for Everest, the world's tallest mountain, begins in March. (Photo by Tashi Sherpa/AP Photo)

Revellers ride during the 54th annual brass band festival in the Serbian village of Guca August 7, 2014. Every year Guca is swamped by thousands of people taking part in the celebration of brass band music. (Photo by Marko Djurica/Reuters)

Transgender Kendra Ferrari, 21, performs during Miss Night Queen beauty contest in Guatemala City, Friday, June 15, 2012. Ferrari won the pageant and will represent the transgender community for one year. (Photo by Rodrigo Abd/AP Photo)

A hot air balloon floats over farm fields south of Washington, Ill., as the sun slips behind clouds on the autumn afternoon of Wednesday, September 24, 2014. (Photo by Ron Johnson/AP Photo/Peoria Journal Star)