Train attendants take part in a parade training as they visit the national flag guard during a patriotic education event ahead of the 90th anniversary of the founding of the Chinese People's Liberation Army (PLA) in Beijing, China July 25, 2017. (Photo by Reuters/China Stringer Network)

Visitors watch dinosaur models at Haitang Bay Rice Paddy Park on January 24, 2018 in Sanya, Hainan Province of China. The Haitang Bay Rice Paddy Park featuring 323 full-size dinosaur models was officially opened to the public on Thursday. (Photo by Yin Haiming/China News Service/VCG via Getty Images)

An Afghan boy jumps off the turret of a Soviet tank on a hilltop on the the outskirts of Kabul, Sunday, March, 4, 2018. (Photo by Rahmat Gul/AP Photo)

Evangelia Platanioti of Greece competes in the Solo Technical Routine at the Glasgow 2018 European Synchronised Swimming Championships, Glasgow, Britain, 06 August 2018. (Photo by Neil Hall/EPA/EFE)

A man sleeps at Beirut's Corniche, a seaside promenade, in Lebanon May 2, 2016. (Photo by Alia Haju/Reuters)

A fisherman throws a net for catching fish with his wife in Yanhu fisherman village near Yangzhou, Jiangsu province, China, 18 October 2018. (Photo by Aleksandar Plavevski/EPA/EFE)

The secretive indri (Indri indri) of Madagascar, the largest living lemur. It is also critically endangered and highly evolutionarily distinct with no close relatives, which makes its branch one of most precarious on the mammal evolutionary tree. In the likely event that the indri goes extinct, we will lose 19m years of unique evolutionary history from the mammal tree of life. (Photo by Pierre-Yves Babelon/Aarhus University)

In this photograph taken on September 22, 2016, a Pakistani devotee decorates symbolic paper boats, an offering to Muslim saint Abdulqadir Jilani as a way of giving thanks after their desire to give birth to a son was fulfilled, before dropping it into the water during an annual ceremony on the banks of the River Ravi in Lahore. The ceremony commemorates a centuries-old tale that Muslim saint Abdulqadir Jilani raised a sunken ship carrying a wedding party, at the pleading of the groom's mother, saving all the occupants. (Photo by Arif Ali/AFP Photo)