Members of the Uniao da Ilha do Governador Samba School perform during the first day of the Special Group Samba Schools parade of Carnival at the Sambadrome in Rio de Janeiro, Brazil, 07 February 2016. (Photo by Luiz Eduardo Perez/EPA)

Nepalese Hindu devotees take part in a bathing ritual on the last day of the month-long Swasthani Festival in the Hanumante River at Bhaktapur on the outskirts of Kathmandu on February 22, 2016. Devotees mark the Swasthani Festival with fasting, and with women in particular undertaking rituals in the hope of a prosperous life for her family and conjugal happiness. (Photo by Prakash Mathema/AFP Photo)

Palestinian boy Mohammad al-Bana, 10, sells mints at a market in Gaza City March 29, 2016. Bana, whose father is unemployed, earns around 10 Shekels ($2.5) per day. The boy starts working after finishing school. He hopes to continue education and become an engineer in the future. (Photo by Mohammed Salem/Reuters)

Female Siberian tiger Dasha yawns in the new enclosure at the zoo in Duisburg, Germany, 30 March 2016. The new facility is three times larger than the old one and will be opened to the public on the same day. (Photo by Roland Weihrauch/EPA)

The “Rabid Transit” Burning Man art car erupts with flames from it's onboard propane poofers during the 4th day of the annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S., August 31, 2017. (Photo by Jim Bourg/Reuters)

Indian Hindu devotees carry an idol of the elephant-headed Hindu deity Ganesha for immersion in a temporary pond near Sangam in Allahabad on September 4, 2017. The Ganesh Chaturthi festival is a popular 11-day religious festival which is annually celebrated across India. (Photo by Sanjay Kanojia/AFP Photo)

Tactics reminiscent of the early American frontier days are now being used in Vietnam. Lieutenant Commander Donald D. Sheppard, UBN, of Coronado, California, aims a flaming arrow at a bamboo hut concealing a fortified Viet Cong bunker on the banks of the Bassac River, Vietnam on December 8, 1967. (Photo by AP Photo)

Filipino children play as they are doing caroling activities on the street near an airport, days before Christmas in Manila, Philippines, 20 December 2017. Filipinos celebrate the longest Christmas in the world which starts as early as September every year. (Photo by Francis R. Malasig/EPA/EFE)