A protester dressed as a clown holds an umbrella over a Swiss police officer on a motorbike during a May Day demonstration in Zurich, Switzerland on May 1, 2017. (Photo by Arnd Wiegmann/Reuters)

Nazi dictator Adolf Hitler greets supporters at a May Day gathering in the Olympic Stadium, Berlin. (Photo by Keystone). 1st May 1938

Students from the University of St Andrews jump into The North Sea, as a good luck tradition before exams start on the East Sands in St Andrews, Fife, Scotland on May 1, 2018. (Photo by Derek Allan/Alamy Live News)

A reveller walks through the streets in the early hours during traditional May Day celebrations in Oxford, Britain, May 1, 2015. (Photo by Dylan Martinez/Reuters)

Two Brits enjoy Saturday night in Leeds, United Kingdom in bank holiday on May 1, 2021, as number of coronavirus cases and deaths keep decreasing in the UK. The government today reported seven new coronavirus deaths and a further 1,907 infections. (Photo by Nb press ltd)

Protesting women shout slogans during a demonstration against sexual violence in front of the governor's mansion in San Juan, Puerto Rico on May 3, 2021. The demonstrators denounce the inaction and slowness of the state in implementing the executive order declaring a state of emergency against gender-based violence. (Photo by Ricardo Arduengo/AFP Photo)

An empty beer bottle stands in front of the buildings of the banking district in Frankfurt, Germany, Friday, May 21, 2021. All people gathering on the square for drinks and food left when the police started checking if they are abiding by the coronavirus restrictions. (Photo by Michael Probst/AP Photo)

People walk along the sea front at Blyth in Northumberland in North East England on Monday, May 24, 2021. (Photo by Owen Humphreys/PA Images via Getty Images)