Women sing and dance as children gather in the background during the so-called parade of children's troops in Rostov-on-Don, southern Russia, May 14, 2015. About 500 children aged from 4 to 10, members of youth military patriotic clubs, honor guards and paratroopers took part in the event, which was organized under the guidance of Commander of Southern Military District Colonel-General Alexander Galkin and was held to honor World War Two veterans and mark the 70th anniversary of the victory over Nazi Germany, according to local media. (Photo by Eduard Korniyenko/Reuters)

Pakistan girls make selfies holding a Pakistan-made weapon displayed at the four-day International Defence Exhibition and Seminar (IDEAS) 2016 in Karachi, Pakistan, Wednesday, November 23, 2016. (Photo by Shakil Adil/AP Photo)

A navy diver storms into the gallery during a military display at Singapore's 52nd National Day celebrations at Marina Bay in Singapore August 9, 2017. (Photo by Edgar Su/Reuters)

Ultra- trailers compete at sunrise on September 2, 2017 in Courmayeur, Italy, during the 15 th edition of the Mount Blanc Ultra Trail (UTMB), a 170 km race around the Mont Blanc crossing France, Italy and Switzerland. The 15 th Ultra- Trail du Mont- Blanc (UTMB) is a mountain ultramarathon with numerous passages in high altitude (>2500 m) and in difficult weather conditions (night, wind, cold, rain or snow). (Photo by Jeff Pachoud/AFP Photo)

In this Thursday, August 17, 2017 photo, a troupe charges and fires their rifles during Tabourida, a traditional horse riding show also known as Fantasia, in Mansouria, near Casablanca, Morocco. Thousands gathered recently in Mansouria, a small town south of the capital Rabat, to attend one of the oldest festivals in Morocco. Nineteen horse troupes came from different parts of the kingdom to celebrate a three-day event that blends courage, skill and tradition. (Photo by Mosa'ab Elshamy/AP Photo)

Though schools around the globe have different start dates, calendars and traditions, the first day of a new term is an exciting time filled with the prospects of gaining more knowledge, making new friends and building community. Here: Schoolchildren attend their first lesson on Knowledge Day in the town of Turov, Zhytkavichy District, Gomel Region, Belarus on September 1, 2017. Knowledge Day marks the beginning of a new school year in Belarus and is celebrated on September 1. (Photo by Viktor Drachev/TASS via Getty Images)

A woman picks marigold flowers used to make garlands and offer prayers, before selling them to the market for the Tihar festival, also called Diwali, in Kathmandu, Nepal on October 17, 2017. (Photo by Navesh Chitrakar/Reuters)

Italy's Mount Etna, Europe's tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, Italy, February 28, 2017. (Photo by Antonio Parrinello/Reuters)