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)

Iranian bodybuilder Sharareh Nobahari, 30, assists her fitness trainees at a gym in Tehran, Iran on September 20, 2019. (Photo by Nazanin Tabatabaee/Reuters)

Hundreds of students take part in the traditional Raisin Monday foam fight on St Salvator’s Lower College Lawn in Scotland on October 21, 2019. The messy display is the culmination of a weekend of festivities where first years say thank you to their more senior student “parents” for mentoring them. (Photo by Jane Barlow/PA Images via Getty Images)

Street artist Irony’s mural of a young woman on Jamaica Street in Liverpool, UK on September 22, 2019. The city has recently been transformed with bold murals painted by local artists on walls and buildings. Recognisable faces including those of the Beatles, Jürgen Klopp and Stephen Hawking. (Photo by Peter Byrne/PA Wire Press Association)

Two cats watch a mouse walking on the pavement in Kuwait City on March 8,2017. (Photo by Yasser Al-Zayyat/AFP Photo)

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)

A US Army M1A2 SEP tank participates in the Strong Europe Tank Challenge 2017 at the military training area in Grafenwoehr, Germany, 12 May 2017. Six North Atlantic Treaty Organization (NATO) nations and partner nations, Austria, France, Germany, Poland, Ukraine and the USA are taking part in this competing exercise. (Photo by Christian Bruna/EPA)