Members of the “Avalon” team wearing 14th century knight costumes fight against each other on the bank of the Yenisei River during the regional amateurs tournament of clubs of historical reconstruction, “The Battle of the Nations 2015. Siberia”, in Krasnoyarsk January 24, 2015. (Photo by Ilya Naymushin/Reuters)

A handout picture provided by Global newsroom of Czech Martin Sonka (C) leading Nigel Lamb (top) of Great Britain and Yoshihide Muroya of Japan (down) along the Mount Fuji prior the third stage of the Red Bull Air Race World Championship in Chiba, Japan on June 1, 2016. (Photo by Predrag Vockovic/EPA/Global Newsroom)

Yang Juan, an employee at Goopal Group, takes a nap in her seat after lunch, in Beijing, China, April 21, 2016. Office workers sleeping on the job is a common sight in China, where a surplus of cheap labour can lead to downtime at work. But in China's technology sector, where business is growing faster than many start-up firms can hire new staff, workers burn the midnight oil to meet deadlines and compete with their rivals. Some companies provide sleeping areas and beds for workers to rest during late nights. (Photo by Jason Lee/Reuters)

Wrecked tanks are seen close to the road that leads to the village of Imber on December 31, 2011 on Salisbury Plain, England. (Photo by Matt Cardy/Getty Images)

A local resident rests on a bench as Mount Bromo volcano erupts in the background in Ngadisari, Probolinggo, East Java, Indonesia January 5, 2016. (Photo by Darren Whiteside/Reuters)

Mount Sinabung is seen during an eruption from Surbakti village in Karo, North Sumatra, Indonesia, April 20, 2015. The local government is preparing the relocation of residents from three of the villages that were destroyed. (Photo by Tibta Pangin/Getty Images/Anadolu Agency)

The Villarrica Volcano is seen at night from Pucon town, Chile, July 12, 2015. Villarrica, located near the popular tourist resort of Pucon, is among the most active volcanoes in South America. (Photo by Cristobal Saavedra/Reuters)

Arrow sports his new elastic booties at a PetSmart in Tempe, Ariz. on Tuesday, June 20, 2017. Phoenix radio station KSLX handed out the protective coverings to protect dogs' paws from the hot pavement, as temperatures in Phoenix are forecasted to hit 120 degrees (48°C). (Photo by Angie Wang/AP Photo)