Indian dancers paint their body like tigers as they perform a Tiger dance during the International day of the Tiger in Calcutta, India, July 29, 2015. Students of Calcutta are taking part in an awareness campaign aiming to draw attention to the threats that tigers face due to habitat loss and poaching. (Photo by Piyal Adhikary/EPA)

A girl jumps over a campfire while celebrating Ivan Kupala Night, a traditional Slavic holiday not far from Kiev on July 6, 2013. During the celebration, originating in pagan times, people plait wreaths, jump over fires, and swim naked. (Photo by Sergei Supinsky/AFP Photo)

Attnedees dressed in Zombie outfits walk down the Gaslamp Quarter outside of the 2015 Comic-Con International in San Diego, California July 8, 2015. (Photo by Sandy Huffaker/Reuters)

Participants take part in the annual Great Spitalfields Pancake Race in aid of London's Air Ambulance in London, Britain February 9, 2016. (Photo by Stefan Wermuth/Reuters)

In this photograph taken on June 28, 2015, a hiker in Hong Kong takes a picture of the city from a walking trail. The southern Chinese territory is crisscrossed by more than 180 miles of designated hiking trails. (Photo by Alex Ogle/AFP Photo)