A truck is seen in a hole after part of the structure of a bridge collapsed into a river in Changchun, Jilin province May 29, 2011. Two truck passengers were injured, while the cause of the accident is still under investigation, local media reported. (Photo by Reuters/China Daily)

A demonstrator is detained during May Day rallies in Santiago May 1, 2013. (Photo by Ivan Alvarado/Reuters)

A woman sports a rainbow painted hand at the annual PrideFest celebration at Civic Center Park in Denver, Colorado June 18, 2016. (Photo by Andy Cross/The Denver Post)

People stand in the middle of the graves and in front of giant kites in the cemetery of Santiago Sacatepequez, Guatemala, November 1, 2015. Dating back 116 years, the tradition of flying kites in the cemetery of of Santiago Sacatepequez, integrates the Catholic feast of All Saints with ancient Mayan practices of honouring the dead. It is believed that the kites connect the living and the dead during the all saints day celebration. (Photo by Jorge Dan Lopez/Reuters)

Police officers detain an opposition protester during a May Day rally in Saint Petersburg, Russia on May 1, 2019. Labor Day or May Day is observed all over the world on the first day of the month of May to celebrate the economic and social achievements of workers and fight for laborers rights. (Photo by Igor Russak/Reuters)

A woman dressed up for Halloween travels on a Metro train in São Paulo, Brazil on October 30, 2017. (Photo by Cris Faga/Rex Features/Shutterstock)

Vehicles are burning as thousands of people take to the streets during the May Day demonstrations on May 1, 2018 in Paris, France. This month celebrates the 50th anniversary of May 68 when France seen millions of students and striking workers, come onto the streets in demonstrations that changed the country. (Photo by Jeff J. Mitchell/Getty Images)

Fireworks and light effects illuminate the night sky from the Taipei 101 skyscraper during New Year's Eve celebrations in Taipei, Taiwan, 01 January 2019. (Photo by Ritchie B. Tongo/EPA/EFE/Rex Features/Shutterstock)