A man in “Red Army” garb hits the pavement during a simulated attack during a re-staging of part of the Long March in Jinggangshan September 14, 2017. The scene brings alive an extraordinary chapter in China's history that established the supremacy of Chairman Mao Zedong and the Communist Party. Deep in the mountains of Jinggangshan in the southeastern province of Jiangxi, a classroom of bank tellers participates in an ideological boot camp that plays into Chinese President Xi Jinping's drive to further consolidate his grip on power. (Photo by Thomas Peter/Reuters)

Long-tailed mayflies (Palingenia longicauda) at Tisza river near Tiszainoka 135km (84 miles) southeast of Budapest, June 23, 2013. Millions of these short-lived mayflies engage in a frantic rush to mate and reproduce before they perish in just a few hours during “Tiszaviragzas” or Tisza blooming season from late spring to early summer every year. (Photo by Laszlo Balogh/Reuters)

A devotee is carried around town in a vessel as part of rituals during the Swasthani Bratakatha festival at Thecho in Lalitpur, Nepal, February 19, 2016. During the month long festival, devotees recite one chapter of a Hindu tale daily from the 31-chapter sacred Swasthani Brata Katha book that is dedicated to God Madhavnarayan and Goddess Swasthani, alongside various other gods and goddess and the miraculous feats performed by them. (Photo by Navesh Chitrakar/Reuters)

A zoo keeper feeds Diego, a three month old howler monkey, which is reared at Edinburgh Zoo, July 29, 2008 in Scotland. (Photo by Jeff J. Mitchell/Getty Images)

Black Nazarene devotees clamber on top of one another to to touch the cross on January 9, 2015 in Manila, Philippines. The Feast of the Black Nazarene culminates in a day long procession on January 9 as barefoot devotees march to see and touch the image of the Black Nazarene. The Black Nazarene is a dark wood sculpture of Jesus brought to the Philippines in 1606 from Spain and considered miraculous by Filipino devotees. The event falls a week ahead of the visit of Pope Francis who will travel to Leyte and Manila during his visit to the Philippines from January 15–19. The visit is expected to attract crowds in the millions as Filipino Catholics flock to catch a glimpse of the leader of the Catholic Church. The Philippines is the only Catholic majority nation in Asia with around 90 percent of the population professing the faith. (Photo by Dondi Tawatao/Getty Images)

An artist's impression of a growing supermassive black hole located in the early Universe is seen in this NASA handout illustration released on June 15, 2011. Using the deepest X-ray image ever taken, astronomers found the first direct evidence that massive black holes were common in the early universe. This discovery from NASA's Chandra X-Ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies. (Photo by Reuters/NASA/Chandra X-Ray Observatory/A.Hobart)