A man carries a dog and wades through a flooded street in Chennai, in the southern Indian state of Tamil Nadu, Wednesday, December 2, 2015. Weeks of torrential rains have forced the airport in the state capital Chennai to close and have cut off several roads and highways, leaving tens of thousands of people stranded in their homes, government officials said Wednesday. (Photo by AP Photo)

In this March 14, 2015 photo, tourists take pictures from a viewing area at Iguazu Falls in Brazil. From walkways and bridges, viewers can count 270 water falls almost 100 meters (330 feet) high. (Photo by Jorge Saenz/AP Photo)

Students in Aone’s elementary school during break in between the class on April 9, 2015. The school has only six students, two of whom are from the same family. Similarly small schools can be found throughout Japan. (Photo by Ko Sasaki/The Washington Post)

Children take part in the “Carnavalito” children's parade during the Blacks and Whites Carnival in Pasto, Colombia, on January 2, 2018. (Photo by Juan Barreto/AFP Photo)

Poshia, 16, who said she is a fashion designer smiles as she holds an umbrella for her relative near princess town, Ghana on November 23, 2018. (Photo by Zohra Bensemra/Reuters)

An Indian cyclist pedals with a child during heavy rain in Mumbai, Maharashtra state, India, Friday, July 24, 2015. Several parts of the city witnessed heavy rain Friday. The monsoon rains which usually hit India from June to September are crucial for farmers whose crops feed hundreds of millions of people. (Photo by Rajanish Kakade/AP Photo)

Cuban soldiers receive combat training at the Cadets School “Antonio Maceo” November 28, 2001, 30 kilometers East of Havana. (Photo by Jorge Rey/Getty Images)

Two girls are detained outside the Currys electrical store in Brixton on August 8, 2011 in London, England. Widespread rioting and looting took place across many parts of London in the early hours of Monday morning in a reaction to earlier rioting in Tottenham in North London. Major disturbances broke out late on Saturday night in Tottenham and the surrounding area after the killing of Mark Duggan, 29 and a father-of-four, by armed police in an attempted arrest on August 4. (Photo by Dan Kitwood/Getty Images)