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)

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

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)

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)

A demonstrator throw a firebomb during clashes with Turkish riot police officers in Istanbul, Turkey, Friday, May 1, 2015. The government assigned 30,000 police officers backed by helicopters as workers and demonstrators determined to defy a government ban, tried to march to iconic Taksim Square, where 35 people were killed during May Day celebration in 1977. (Photo by Emrah Gurel/AP Photo)

Nursing and care personnel lay on the floor in the ICU unit, during a demonstration on International Nursing and Care day, at the Mont Legia Hospital in Liege, Belgium, Wednesday, May 12, 2021. Hospital personnel around Belgium took part in various actions around the country on Wednesday to highlight the work they do and demand better recognition. (Photo by Valentin Bianchi/AP Photo)

A Palestinian father evacuates his wounded daughter from the rubble of a destroyed house after an Israeli air strike in Gaza City, 16 May 2021. A total of 174 people have been killed in Israeli raids on Gaza, including 47 children and 29 women, the Palestinian Ministry of Health said on Sunday. In response violent confrontations between Israeli security forces and Palestinians in Jerusalem, various Palestinian militant factions in Gaza launched rocket attacks on Israel since 10 May, resulting in retaliatory strikes by Israel on Gaza. (Photo by Haitham Imad/EPA/EFE)

Activists from the climate action group Ocean Rebellion perform a stunt outside the Science Museum, in London, United Kingdom on May 19, 2021. (Photo by Hannah McKay/Reuters)