Mark Dill and Brit Thacker practice acro-yoga as approximately 70,000 people from all over the world gather for the 30th annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S. August 29, 2016. (Photo by Jim Urquhart/Reuters)

The sun streaks through the fall foliage at sunrise along the Potomac River in Arlington, Va., Wednesday, November 4, 2015 on a warm fall day in the nation's Capitol area. (Photo by J. David Ake/AP Photo)

Residents with faces covered in ash ride on a motorcycle as Mount Sinabung volcano erupts, in Sukandebi village in Karo Regency, Indonesia's North Sumatra province, Indonesia June 13, 2015, in this photo taken by Antara Foto. (Photo by Rony Muharrman/Reuters/Antara Foto)

The Soyuz TMA-17M spacecraft carrying the International Space Station (ISS) crew blasts off from the launch pad at the Baikonur cosmodrome, Kazakhstan, July 23, 2015. The Russian rocket carries Russian cosmonaut Oleg Kononenko, U.S. astronaut Kjell Lindgen and Japan astronaut Kimiya Yui. (Photo by Shamil Zhumatov/Reuters)

Seven year old Hungarian herding dog Derci runs along the Olympiaberg hill during stormy weather in Munich, southern Germany, Monday, January 4, 2016. (Photo by Matthias Balk/DPA via AP Photo)

A photograph of Cuba's former President Fidel Castro decorates a wall inside a state-run market in Havana, March 8, 2016. (Photo by Alexandre Meneghini/Reuters)

Subway passengers walk past bronze sculptures representing the Soviet people at the Ploshchad Revolyutsii metro station in Moscow, on November 14, 2012. The station was opened in 1938. (Photo by Kirill Kudryavtsev/AFP Photo)

In this Friday, February 6, 2015 photo, sandhill cranes begin to stir after resting for the night at a roosting location along their winter migration route in Cecilia, Ky. According to counts made by biologists with the Kentucky Fish and Wildlife Resources, about 12,000 of the birds have stopped in Cecilia this week during their winter northward migration on their way to their nesting grounds in the Great Lakes region. (Photo by David Stephenson/AP Photo)