A displaced Yemeni woman from Hodeida fills water containers at a make-shift camp in a village in the northern district of Abs in the country's Hajjah province, on May 9, 2019. The Yemeni conflict has triggered what the United Nations describes as the world's worst humanitarian crisis, with 3.3 million people still displaced and 24.1 million in need of aid. (Photo by Essa Ahmed/AFP Photo)

Children jump into the water despite strong waves after a strong downpour at Manila's bay, Philippines, Wednesday, July 17, 2019. Schools in metropolitan Manila have been suspended as Tropical Storm Danas, locally named Falcon, continue to enhance the southwest monsoon as it maintains its strength bringing heavy rains over parts of Luzon and Visayas according to the Philippine Atmospheric Geophysical and Astronomical Services Administration. (Photo by Aaron Favila/AP Photo)

In this April 14, 2014 file photo, Hamamatou Harouna, 10, who lost the use of her legs to polio, crawls to the restroom on the grounds of the Catholic Church where she and hundreds of others found refuge after fleeing violence in her village, in Carnot, Central African Republic. Health authorities on Tuesday, August 25, 2020 are expected to declare the African continent free of the wild poliovirus after decades of effort, though cases of vaccine-derived polio are still sparking outbreaks of the paralyzing disease in more than a dozen countries. (Photo by Jerome Delay/AP Photo/File)

The Royal casket of King George Tupou V is carried towards the Royal Tombs during the State Funeral held for King George Tupou V at Mala'ekula on March 27, 2012 in Nuku'alofa, Tonga. King George died in Hong Kong on March 18th after six years as the King. (Photo by Sandra Mu/Getty Images)

Members of the Communist New Fourth Army on parade. Note how the modern equipment contrasts with the shoeless soldiers in the foreground. (Photo by Hulton Archive/Getty Images). 6th July 1946

Men look out from a carriage train as it leaves from the Nizamuddin Railway Station on February 06, 2012 in New Delhi, India. The Nizamuddin Railway Station serves as the main station connecting all major cities, and is served by Northern Railways. (Photo by Daniel Berehulak/Getty Images)

A sewer cleaner of Dhaka City Corporation cleaning out the city's sewers on May 03, 2017 in Dhaka, Bangladesh. Despite a rise in the number of deaths of manhole workers every year, workers regularly go into the manholes without any protective gear. (Photo by Zakir Chowdhury/Barcroft Images)