A humanoid robot named “Yangyang” shows a facial expression during its demonstration at the Global Mobile Internet Conference (GMIC) 2015 in Beijing, China, April 29, 20155. The android was produced jointly by China's Shanghai Yangyang Intellegent Robot Science Service center and Japanese professor Hiroshi Ishiguro, with the aim of popularising robotics among the young. (Photo by Kim Kyung-Hoon/Reuters)

Members of contemporary circus group perform inside the subway train, amid the energy crisis in Prague, Czech Republic on March 2, 2023. (Photo by David W. Cerny/Reuters)

A couple shares a light moment in a Mass Transit Railway (MTR) subway train in Hong Kong, China on August 28, 2019. (Photo by Anushree Fadnavis/Reuters)

Commuters wear protective face masks as they walk through a subway station, in Sao Paulo, Brazil, Wednesday, December 1, 2021, amid the COVID-19 pandemic. Brazil joined the widening circle of countries to report cases of the omicron variant. (Photo by Andre Penner/AP Photo)

Two railway workers chat in front of a flower mural inside a subway station visited by foreign reporters during a government organised tour in Pyongyang, North Korea October 9, 2015. (Photo by Damir Sagolj/Reuters)

A surfer rides a large wave at El Bocal during the Vaca Gigante (Big Cow) giant wave surf competition in Santander, northern Spain December 17, 2016. (Photo by Vincent West/Reuters)

Kite-surfers practice in a water reservoir at the shores of the Mediterranean sea close to the southern Israeli kibbutz of Ziqim during stormy weather, on December 20, 2021. (Photo by Menahem Kahana/AFP Photo)

Surfers take to the waves at Bondi Beach on October 16, 2021 in Sydney, Australia. COVID-19 restrictions eased across NSW on Monday 11 October for fully vaccinated residents after the state passed its 70 per cent double vaccination target. (Photo by Brook Mitchell/Getty Images)