Afghan air force 2nd Lt. Niloofar Rhmani walks the flight line at Shindand Air Base, Afghanistan, prior to her graduation from undergraduate pilot training, on May 13, 2013. Rhmani made history on May 14, when she became the first female to successfully complete undergraduate pilot training and earn the status of pilot in more than 30 years. She will continue her service as she joins the Kabul Air Wing as a Cessna 208 pilot. (Photo by Senior Airman Scott Saldukas/USAF)

A fairy tale and movie-themed gingerbread house creation, featuring a reindeer, made by pastry students of the San Ysidro Adult School Culinary Arts program is pictured during their 9th annual gingerbread house competition in San Ysidro, California December 9, 2014. The students' voting results will be delivered back to their class but the official judging will be performed by chefs and culinary experts during the 9th annual event. (Photo by Mike Blake/Reuters)

Historical reenactor Troy Kotz poses with a mug of wassail in the parlor of the Guyon-Lake-Tysen House during the annual Candlelight Tour of Historic Richmond Town, Saturday, December 13, 2014, in the Staten Island borough of New York. The annual event lets visitors experience an authentic Victorian Christmas. This image was made using the TinType by Hipstamatic iPhone app. (Photo by Chad Rachman/New York Post)

Relatives of the crashed AirAsia plane passengers pray at Juanda Airport, in Surabaya, Indonesia, 31 December 2014. Indonesian rescuers retrieved three more bodies from the sea on 31 December but the search to recover more victims from the AirAsia plane crash was hampered by bad weather, the recue chief said. AirAsia Indonesia flight QZ8501 crashed into the Java Sea on 28 December, about halfway through a two-hour flight between Surabaya, Indonesia's second largest city, and Singapore. (Photo by Made Nagi/EPA)

The Hubble Space Telescope is shown following its release from the space shuttle Discovery Wednesday, February 19, 1997. The Hubble Space Telescope, one of NASA'S crowning glories, marks its 25th anniversary on Friday, April 24, 2015. With more than 1 million observations, including those of the farthest and oldest galaxies ever beholden by humanity, no man-made satellite has touched as many minds or hearts as Hubble. (Photo by AP Photo/NASA)

A photograph made available on 02 October 2016 showing Indian people dressed in traditional attire performing the Garba dance, a ritual performed to appease Goddess Durga, in a religious event named, “Abhivyakti 2016” during the nine-day long Navratri festival in Bhopal, India, 01 October 2016 Celebrated twice a year during the spring and the fall season, the Navratri festival is dedicated to the Hindu Goddess Durga. (Photo by Sanjeev Gupta/EPA)

In this February 22, 2018 photo, a couple looks at a bag made out of Venezuelan Bolivars in La Parada, Colombia, on the border with Venezuela. Each collector item produced by Richard Segovia, sitting at the table, fetches between $10 and $15 – a huge markup from the pennies that bolivars retrieve on Venezuela's black market. (Photo by Fernando Vergara/AP Photo)

Sugar gliders, Candy and Popcorn, enjoy their favourite food, Nectar, at Wild Life Sydney Zoo on February 14, 2017 in Sydney, Australia. The treat made up of honey, high protein baby cereal and egg yolks is the human equivalent to chocolate to the Sugar Gliders. St. Valentine's Day or the Feast of Saint Valentine began as a celebration of the early Christian Saint Valentinus. From the 18th Century onwards it has steadily transformed into a celebration of romantic love and sentiment in many countries around the world. (Photo by James D. Morgan/Getty Images)