Devotees ride on the roof of a train as they return to the city after attending the final prayers on the first phase of Bishwa Ijtema in Dhaka January 11, 2015. Hundreds of thousands of pilgrims congregated in the Bangladeshi capital Dhaka as the first phase of this year's Bishwa Ijtema, one of the biggest Islamic gatherings in the world after the Haj in Saudi Arabia, came to an end. (Photo by Reuters/Stringer)

A panda bear sits on a logs in a zoo on January 15, 2015 in Hangzhou, China. (Photo by Feature China/Barcroft Media)

A street artist dances tango in Buenos Aires, Argentina, Tuesday, January 20, 2015. Tango is a partner dance that originated in the 1890's along the Rio de la Plata, the border between Uruguay and Argentina. UNESCO approved in 2009, a joint proposal by the two nations to include the dance in its Intangible Cultural Heritage List. (Photo by Rodrigo Abd/AP Photo)

Ukrainians pour water on each other on a street in Lviv, Ukraine, 02 May 2016. The tradition of pouring water was an ancient spring ritual of cleansing on first Monday after Orthodox Easter. (Photo by Mykola Tys/EPA)

A model is seen backstage, having makeup applied, ahead of the Casely-Hayford show during The London Collections Men SS17 at BFC Show Space on June 11, 2016 in London, England. (Photo by Jeff Spicer/Getty Images)

Hundreds of people pack the Canaveral national seashore's Playalinda Beach as a United Launch Alliance Atlas V rocket, carrying a U.S. Navy communications satellite, lifts off from Complex 41 at the Cape Canaveral Air Force Station, Friday, June 24, 2016, in Cape Canaveral, Fla. The satellite is designed to significantly improve ground communications for U.S. forces on the move. (Photo by Craig Rubadoux/Florida Today via AP Photo)

Russian artist Maria Gasanova adjusts her make-up as she finishes “The Siberian Beauty” body art work from her “The Alive Painting” series before the opening ceremony of the Cultural Universiade as part of preparation for the 2019 Winter Universiade Krasnoyarsk, in the Siberian city of Krasnoyarsk, Russia, December 9, 2016. (Photo by Ilya Naymushin/Reuters)

“A Mothers Tail”. A baby cub pulls on his mother's tail to get attention. Photo location: Masai Mara, Kenya. (Photo and caption by Tori Marsh/National Geographic Photo Contest)