Hemispheric color differences on Saturn's moon Rhea are apparent in this false-color view from NASA's Cassini spacecraft in this March 2, 2010 file photo. (Photo by Reuters/NASA/JPL/SSI)

A young Chinese girl dressed in Christmas costume, hugs a pedestrian on a street to celebrate Christmas in Nanjing city, east China's Jiangsu province, 23 December 2015. (Photo by Imaginechina/Splash News)

Policemen and residents run as waves from a tidal bore surge past a barrier on the banks of Qiantang River in Haining, Zhejiang province August 31, 2011. As Typhoon Nanmadol approaches eastern China, the tides and waves in Qiantang River recorded its highest level in 10 years, local media reported. (Photo by Reuters/China Daily)

People walk past part of an outdoor display as preparations continue for the upcoming pop culture convention Comic Con in San Diego, California, U.S., July 17, 2018. (Photo by Mike Blake/Reuters)

Internationally acclaimed German three-dimensional artist Manfred Stader adds finishing touches to his artwork in Cape Town, South Africa on 21 November 2010. Stader created this masterpiece to celebrate the opening of Speedo's first dedicated concept store in Africa. (Photo by Foto24/Gallo Images/Getty Images)

A visitor tries out Lenovo augmented reality glasses with the Star Wars Jedi Challenges during the Mobile World Congress in Barcelona, Spain, February 26, 2018. The Mobile World Congress, the world' s biggest mobile fair, is held in Barcelona from February 26 to March 1. (Photo by Yves Herman/Reuters)

One of the last incoming trains arrives outside the main train station after Deutsche Bahn cancelled all train traffic in Germany due to heavy storms, Frankfurt, Germany, Thursday, January 18, 2018. (Photo by Michael Probst/AP Photo)

A Palestinian girl with her body painted by special effects makeup artist Alaa Abu Mustafa, 20, sits on a boat in the southern Gaza Strip, March 22, 2018. (Photo by Ibraheem Abu Mustafa/Reuters)