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)

Bikers push their motorbikes during a traffic block as they take part in the “Enduropale” motorcycle endurance race on the beach of Le Touquet, northern France, February 1, 2015. About 1100 motorbike and 600 quad bike riders descend on Le Touquet every year for the racing endurance event. (Photo by Pascal Rossignol/Reuters)

A Hindu worshipper throws vegetables into the crater as offerings during the Kasada Festival at Mount Bromo in Probolinggo, Indonesia's East Java province, August 1, 2015. Every year people gather for the annual festival where offerings of rice, fruit, vegetables, livestock or money are made to Hindu gods at the active volcano to ask for blessings and assure a bountiful harvest. (Photo by Reuters/Beawiharta)

A performer is covered in chocolate sauce at the Notting Hill Carnival on August 28, 2011 in London, England. The annual carnival, which is the largest of it's kind in Europe and is expected to attract around 1 million revellers, has taken place every August Bank Holiday since 1966. (Photo by Oli Scarff/Getty Images)

Artists perform during the opening show directed by German director Volker Hesse, on the opening day of the Gotthard rail tunnel, at the fairground Rynaecht at the northern portal in Erstfeld, Switzerland, Wednesday, June 1, 2016. The construction of the 57 kilometer long tunnel began in 1999, the breakthrough was in 2010. After the official opening on June 1, the commercial operation will start in December 2016. (Photo by Ruben Sprich\Pool Photo via AP Photo)

A former paratrooper demonstrates his strength and skills while lifting a chair during the celebrations for the Paratroopers Day at the Central park in the Siberian city of Krasnoyarsk, Russia, August 2, 2015. Paratroopers are an elite unit of the Soviet Army, and everyone in the country recognize their blue berets. (Photo by Ilya Naymushin/Reuters)

The Eiffel Tower is illuminated during the traditional Bastille Day fireworks display in Paris, July 14, 2013. (Photo by Fred Dufour/AFP Photo)

Iranian mourners cover themselves with mud during Ashoura, marking the death anniversary of Imam Hussein, the grandson of Islam's Prophet Muhammad, at the city of Bijar, west of the capital Tehran, Iran, Thursday, November 14, 2013. Hussein, one of Shiite Islam's most beloved saints, was killed in a 7th century battle at Karbala, Iraq. (Photo by Ebrahim Noroozi/AP Photo)