Stranded cars remain in a flooded street during an intense rainstorm in Havana, on April 29, 2015. Two people were killed, three buildings collapsed and another 24 suffered some kind of damage due to the heavy rain that affected several sectors of Havana Wednesday. (Photo by Yamil Lage/AFP Photo)

A young Chinese girl kicks during a kung-fu class at Ritan Park on June 11, 2016 in Beijing, China. Ritan, meaning “sun altar”, is among the oldest parks in Beijing, built in the early 1500s during the Ming dynasty for the emperor to make sacrifices to the sun. (Photo by Kevin Frayer/Getty Images)

China's Wang Yan performs on the balance beam during the artistic gymnastics women's individual all-around final at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Thursday, August 11, 2016. (Photo by Julio Cortez/AP Photo)

A U.S. Army B-24 Liberator Bomber is hailed by a ground crewman as it takes off over a line of shark- nosed fighter planes at an advanced base in China on a mission on October 10, 1943, to bomb Japanese installations. (Photo by AP Photo)

The view at night from the Shanghai Tower in Shanghai, China on August 7, 2015. The tower is technically smaller than the Burj Khalifa in Dubai but, while the observation deck of Dubai’s mega-structure is at 556m, the Shanghai Tower’s is at 561m, meaning the view is a little higher. (Photo by Paul Reiffer/REX Shutterstock)

A partial solar eclipse is seen as a labourer works at a construction site in Phnom Penh, Cambodia, March 9, 2016. (Photo by Samrang Pring/Reuters)

A man walks on the road between Nouahibou and Nouakchott, where three Spanish aid workers were abducted in Mauritania, December 3, 2009. (Photo by Rafael Marchante/Reuters)

A dog walker on Longsands beach before sunrise in Tynemouth, UK on April 1, 2016. (Photo by Owen Humphreys/PA Wire)