Clouds gather as walkers pause atop a ridge in Mountain View, California January 7, 2016. (Photo by Noah Berger/Reuters)

Dancer Elizabeth Suarez, 29, gets ready to perform at the backstage of a cinema where the “Cuerda Viva” (Live Strings) alternative music festival is taking place, in Havana, February 26, 2016. (Photo by Alexandre Meneghini/Reuters)

In this April 4, 2015, photo, Marilia Skraba, center, of Brazil, applies makeup while waiting to compete in the Miss Viva Las Vegas contest during the Viva Las Vegas Rockabilly Weekend in Las Vegas. The event draws thousands of people from around the world. (Photo by John Locher/AP Photo)

Summit, an Australian shepherd, makes a leaping catch of a frisbee at the pet trade fair (Heimtiermesse) at Velodrom on November 2, 2012 in Berlin, Germany. Exhibitors are showing the latest trends in collars, snacks and other accessories for cats, dogs and other household pets. (Photo by Sean Gallup)

A picture taken on August 7, 2017 shows a Snow Leopard (Panthera uncia) at the NABU center (Nature and Biodiversity Conservation Union), a German organization that aims at reintroducing the panther and fighting against poaching, near the Issyk Kul lake, in the outskirts of Semenovka village, some 330 kilometers southeast of Bishkek, the capital of Kyrgyzstan. (Photo by Vyacheslav Oseledko/AFP Photo)

Magbola Alhadi, 20, and her three children pose for a portrait in Jamam refugee camp in Maban County, South Sudan on August 11th, 2012. Magboola and her family weathered aerial bombing raids for several months, but decided it was time to leave their village of Bofe the night that soldiers arrived and opened fire. With her three children, she travelled for 12 days from Bofe to the town of El Fudj, on the South Sudanese border. The most important thing that Magboola was able to bring with her is the saucepan she holds in this photograph. It wasn't the largest pot that she had in Bofe, but it was small enough she could travel with it, yet big enough to cook sorghum for herself and her three daughters (from left: Aduna Omar, 6, Halima Omar, 4, and Arfa Omar, 2) during their journey. (Photo by Brian Sokol/Panos Pictures)

In this February 2, 2014 photo, people take pictures inside a cave at Apostle Islands National Lakeshore in northern Wisconsin, which has been transformed into a dazzling display of ice sculptures by the arctic siege gripping the Upper Midwest. (Photo by Brian Peterson/AP Photo/Minneapolis Star Tribune)

Fog hangs between pine trees in a forest near Neubrueck, eastern Germany, on November 20, 2012. Meteorologists forecast cloudy sky and temperatures around 5 degrees Celsius for the region. (Photo by Patrick Pleul/AFP Photo)