Skulls are seen at the witch doctor kiosk during the day of offerings to the “Pachamama” (Mother Earth) in El Alto, Bolivia, August 1, 2016. Pachamama is a goddess revered by the indigenous people of the Andes. She is also known as the earth/time mother. In Inca mythology, Pachamama is a fertility goddess who presides over planting and harvesting, embodies the mountains, and causes earthquakes. (Photo by David Mercado/Reuters)

A mahout bathes his elephant in the river Sabarmati on a hot summer day in Ahmedabad, India May 21, 2017. (Photo by Amit Dave/Reuters)

A Chinese People's Liberation Army soldier marches with members of an honor guard as they prepare for a welcome ceremony for visiting Luxembourg's Prime Minister Xavier Bettel outside the Great Hall of the People in Beijing, Monday, June 12, 2017. (Photo by Andy Wong/AP Photo)

Robot inventor Wu Yulu sits on a rickshaw driven by a robot which he invented in his village in rural Beijing's Tongzhou district, China, 17 November 2016. The 54-year-old Chinese farmer living in rural Beijing's Tongzhou district invented 63 robots in the past 30 years. Wu, who only received primary school education, plans to give up the agricultural work for his robot products. He regularly participates in exhibitions, transfers patent rights and teaches at the university to earn money. (Photo by Wu Hong/EPA)

Train attendants take part in a parade training as they visit the national flag guard during a patriotic education event ahead of the 90th anniversary of the founding of the Chinese People's Liberation Army (PLA) in Beijing, China July 25, 2017. (Photo by Reuters/China Stringer Network)

Members of the San Francisco Gay Freedom Day Marching Band and Twirling Corps do their thing down San Francisco's Market Street, June 27, 1982. Police estimate the crowd to be 300,000 for the Lesbian/Gay Freedom Day parade and rally. (Photo by Carl Viti/AP Photo)

Visitors make snowmen beside a pool at a hot spring in Hangzhou, in China's eastern Zhejiang province on January 26, 2018. China's central and eastern regions have been hit by heavy snowfalls in recent days, causing disruptions to flight and train schedules. (Photo by AFP Photo/China Stringer Network)

A tourist clad in Japanese kimono takes a picture in front of s portrait shop in Tokyo's Asakusa district, Thursday, February 15, 2018. Asakusa is a popular district four tourists in the capital. (Photo by Shizuo Kambayashi/AP Photo)