Visitors looks at the flying car Pegasus 1, built by French entrepreneur Jerome Dauffy at Paris Air Show, in Le Bourget, east of Paris, France, Tuesday, June 20, 2017. Aviation professionals and spectators are expected at this week's Paris Air Show, coming in, in a thousands from around the world to make business deals. (Photo by Michel Euler/AP Photo)

A boy poses with a butterfly on his face during a photocall to promote the “Sensational Butterflies” exhibition at the Natural History Museum in central London, on March 25, 2013. With around 400 live tropical butterflies and moths living in the temporary facility, visitors will get the chance to see them flying freely as well as looking for emerging butterflies at the hatchery window. Running from March 29 to September 15, 2013, the exhibition is housed in a structure in the museum grounds. (Photo by Leon Neal/AFP Photo)

Tourists look at other festival-goers playing in the mud during the Boryeong Mud Festival at Daecheon beach in Boryeong, about 190 km (118 miles) southwest of Seoul, July 19, 2013. About 2 to 3 million domestic and international tourists visit the beach during the annual mud festival, according to the festival organisers. (Photo by Lee Jae-Won/Reuters)

A Syrian rebel walks past Sham 2, a homemade armored vehicle, in Bishqatin, Syria, on December 8, 2012. From a distance it looks rather like a big rusty metal box but closer inspection reveals a homemade armored vehicle waiting to be deployed. Sham II, named after ancient Syria, is built from the chassis of a car and touted by rebels as “100 percent made in Syria”. (Photo by Herve Bar/AFP Photo)

«Little Red Riding Hood». “The moment I pulled this sweater out of the drawer for Frankie I knew what I wanted for my picture today. I envisioned the look, the style, and the composition. When working with a 2 year old it is never easy to actually get the shot you want, especially when they decide to skip nap time. But I really like how this one turned out” – Rich. (Photo by Rich)

A Palestinian young woman from the Birzeit University looks on during clashes with Israeli security forces in Beit El, on the outskirts of the West Bank city of Ramallah, on October 7, 2015. New violence rocked Israel and the Israeli-occupied West Bank, including a stabbing in annexed east Jerusalem, even as Israel and Palestinian president Mahmud Abbas took steps to ease tensions. (Photo by Abbas Momani/AFP Photo)

Humboldt Penguins swim in their pool as a keeper looks on through a spherical window during the annual stocktake press preview at London Zoo in Regents Park in London Monday, January 4, 2016. A requirement of ZSL London Zoo's license, the annual audit takes keepers a week to complete and all of the information is shared with zoos around the world via the International Species Information System, where it's used to manage the worldwide breeding programmes for endangered animals. (Photo by Alastair Grant/AP Photo)

American soldiers with the 173rd Airborne Brigade Battle Company, on a battalion-wide mission in the Korengal Valley, looking for caves, weapons caches and known Taliban leaders, 2007. Tanner Stichter tends to Spc. Carl Vandeberge in the bushes moments after Vandeberge was shot in the stomach during a Taliban ambush, which killed one soldier and wounded two others. (Photo by Lynsey Addario)