An exile Tibetan monk gestures as he makes a point in a dialectics debate with another monk, sitting right, at the Kirti monastery in Dharmsala, India, Monday, January 18, 2016. The debate is an essential part of their training as Buddhist monks. (Photo by Ashwini Bhatia/AP Photo)

In this October 29, 2013 photo, Daniel smokes marijuana inside his apartment where he uses a hydroponics system to grow his weed in Mexico City. “I'm not a narco, dude. I just like to smoke”, said Daniel, who spoke on condition that his last name not be used because, he said, his home-grow operation is "super-illegal" despite being for personal use only. (Photo by Eduardo Verdugo/AP Photo)

Canadian slackliner Mia Noblet walks on a slackline (25mm wide, 3mm thick and 60m long) during “Tianmen Mountain Female High-Heeled Highline Challenge” at Zhangjiajie National Forest Park on May 27, 2018 in Zhangjiajie, Hunan Province of China. 23-year-old Canadian slackliner Mia Noblet became the first one who finished the challenge in 22 minutes and 36 seconds while 32-year-old French slackliner Mini Guesdon broke the record in 9 minutes and 24 seconds during her second attempt on Sunday. (Photo by VCG/VCG via Getty Images)

A woman toes a tube carrying a man during the Ice and snow carnival at Taoranting park in Beijing, China, January 25, 2016. (Photo by Kim Kyung-Hoon/Reuters)

French President Emmanuel Macron performs at the Shrine Africa in Lagos on July 3, 2018. French President Emmanuel Macron has arrived in Abuja for a meeting with his Nigerian counterpart Muhammadu Buhari, in his latest attempt to forge closer ties with English- speaking Africa. (Photo by Ludovic Marin/AFP Photo)

An American soldier walks ahead of an MKIV (Mark IV) British-made tank, circa 1918. (Photo by Hulton Archive/Getty Images)

Framed by the setting sun, an American Bison grazes at the Tallgrass Prairie National Preserve on Tuesday, April 28, 2015, near Strong City, Kan. The buffalo herd at Tallgrass is one of the few herds of wild bison left in the United States. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

People look at huge waves crashing on the San Esteban de Pravia seafront, northern Spanish region of Asturias February 8, 2016. (Photo by Eloy Alonso/Reuters)