In this undated photo made available by journal Nature on January 15, 2014, a northern bald ibis (Geronticus eremita) flies in Tuscany, Italy. A new study released Wednesday, January 15, 2014 says the birds choreograph the flapping of their wings, getting a boost from an updraft of air in the wake of the flapping wings by flying behind the first bird and off to the side. When a flock of birds take advantage of these aerodynamics, they form a V. (Photo by Markus Unsöld/AP Photo)

Singer, songwriter, actress and philanthropist Miley Cyrus, L, takes a selfie while doing her signature tongue-out pose with GMU students Samaria Moss, 18, C, of Spottsylvania, VA, Jaide Tarwid, 18, from Wisconsin, and Zimuzo Okala, 19, of Chesapeake, VA, (blocked) as Cyrus makes a campaign visit for Hillary Clinton and Tim Kaine in Northern Virginia at George Mason University on Saturday, October 22, 2016 in Fairfax, VA. (Photo by Jahi Chikwendiu/The Washington Post)

Fighters from Germany take up position before competing in the Medieval Combat World Championship at Malbork Castle, northern Poland, April 30, 2015. Medieval combat is a full contact sport that revives the foot based tournament fighting of medieval Europe. Countries fight in refereed matches where the objective is to get the opposing team to the floor. There are also duels with polearms, swords and shields where the number of hits landed are scored. The fighters, both male and female, wear heavy armours and weapons, mostly replicas of authentic pieces, and fight following the knights code of conduct. According to organizers, 25 nations from 6 continents are taking part in the Championships, which started on April 30 and will go on until May 3. (Photo by Kacper Pempel/Reuters)

In this Monday, June 15, 2015 photo, Ahmad Abu Jereda, 16, carries Max, the male lion cub, as he passes by Palestinians at the main garden in Gaza City, in the northern Gaza Strip. A pair of lion cubs are stuck at a Gaza-Israel border crossing en route to a Jordan animal sanctuary, after being kept for a year by a family in crowded Gaza. Saduldin al-Jamal had bought the cubs from the Gaza zoo, hit during last summer's Israel-Hamas war. His family would take them to parks or the beach and children – those brave enough – would come up to pet them. (Photo by Adel Hana/AP Photo)

People help a dancer as he falls on stilts in honor of Saint Mary Magdalene in a street for the traditional “Danza de Los Zancos” (Los Zancos Dance), in the small town of Anguiano, northern Spain, Saturday, July 23, 2016. As an ancient tradition for more than 4th centuries, eight young people from the town balance on stilts down the old street, turning to the sound of folk music played on a pipe and drum. (Photo by Alvaro Barrientos/AP Photo)

Indian mourners perform a cremation on the roof of a building overlooking The Manikarnika Ghat in Varanasi on August 23, 2016. India's holy city of Varanasi has been forced to halt cremations along the banks of the sacred river Ganges as deadly floods from monsoon rains hit parts of the country, an official said. More than 100,000 people have been forced from their homes in recent days in northern Uttar Pradesh and neighbouring Bihar states as rain-swollen rivers burst their banks. (Photo by Sanjay Kanojia/AFP Photo)

Chacha, the male chimp, screams at a worker in Sendai, northern Japan, Thursday, April 14, 2016 after fleeing from a zoo. The chimpangzee tried desperately to avoid being captured by climbing an electric pole. Chacha was on the loose nearly two hours Thursday after it disappeared from the Yagiyama Zoological Park in Sendai, the city that's hosting finance ministers from the Group of Seven industrialized nations in May. (Photo by Kyodo News via AP Photo)

A Syrian boy is comforted as he cries next to the body of a relative who died in a reported airstrike on April 27, 2016 in the rebel-held neighbourhood of al-Soukour in the northern city of Aleppo. The Syrian army was preparing an offensive to retake the whole of Aleppo, as fighting in the divided second city killed 38 civilians in a new blow for a tattered truce. Nearly 200 people have been killed in Aleppo in the past week as rebels have pounded government-held neighbourhoods with rocket and artillery fire and the regime has hit rebel areas with air raids. (Photo by Karam Al-Masri/AFP Photo)