Revellers celebrate “Ash Monday” by participating in a colourful “flour war”, a traditional festivity marking the end of the carnival season and the start of the 40-day Lent period until the Orthodox Easter, in Galaxidi, Greece February 19, 2018. (Photo by Alkis Konstantinidis/Reuters)

Indonesian students go to school via a makeshift suspension bridge in Ngemplak, Boyolali regency, Indonesia on November 15, 2017. The lack of access to roads makes students every day to cross the dangerous waterways to go to school. (Photo by Arief Setiadi/Pacific Press/Barcroft Images)

A traffic policeman hides a rose behind his back before giving it to a female driver ahead of International Women's Day in Ryazan, Russia on March 7, 2017. (Photo by Alexander Ryumin/TASS via Getty Images)

Satrio smokes at a kiosk after elementary school on March 3, 2017 in Yogyakarta, Indonesia. Satrio has smoked up to one pack a day and began when he was six years old. (Photo by Ulet Ifansasti/Getty Images)

Female soldiers march during a military parade marking the country's Independence Day in Caracas, Venezuela, Wednesday, July 5, 2017. Venezuela is marking 206 years of their declaration of independence from Spain. (Photo by Ariana Cubillos/AP Photos)

A lemur licks a block of ice containing fruit at Rome's Bioparco zoo, Wednesday, July 5, 2017. Zookeepers at the Bioparco often give animals ice blocks with either fruit or meat on hot summer days. (Photo by Gregorio Borgia/AP Photo)

A college girl takes part in the Holi festival celebrations in Bhopal, India, 19 March 2019. Holi is celebrated on the full moon day and marks the beginning of the spring season. Holi will be celebrated as the Hindu spring festival of colors across the country on 21 March. (Photo by Sanjeev Gupta/EPA/EFE)

Children wearing military uniform take part in a parade, held by Russian servicemen, pupils of infant and primary schools, which is a public event to honour World War Two veterans and to mark the upcoming Victory Day, in Rostov-on-Don, Russia on April 25, 2019. (Photo by Sergey Pivovarov/Reuters)