Police detain a protester after marching on Taksim Square to celebrate May Day in Istanbul, Turkey.

Police officers prevent demonstrators from marching during a May Day protest on Labour Day in Algiers, Algeria.

Protesters dressed as clowns pose beside a Swiss police car during a May Day demonstration in Zurich, Switzerland.

A look-alike of Adolf Hitler from the Netherlands attends a march of far-right supporters of the party 'Die Rechte (The Rights)' during a May Day rally through the streets of Duisburg, Germany.

A worker holds a flag during a May Day protest near the National Monument (Monas) in Jakarta, Indonesia.

People carry a banner reading 'Union, Commitment and Victory' during a May Day rally in Havana, Cuba.

A protester raises her fist during a May Day rally in Manila, Philippines.

Supporters of the Russian Communist party take part in a May Day rally in central Moscow, Russia.

French CRS riot police stand guard during clashes with protesters as part of the traditional May Day labor union march with French unions and yellow vests protesters in Paris.

Palestinians climb over a tree during a rally marking International Workers' Day, or Labour Day, in Gaza City.

Turkish riot police scuffle with a group of protesters as they attempted to defy a ban and march on Taksim Square to celebrate May Day in Istanbul, Turkey.

The paint covered logo of Swiss bank Credit Suisse is seen after a May Day demonstration at the bank's branch office in Zurich, Switzerland.

People sing 'The Internationale', during a rally organised by the communist-affiliated PAME commemorating May Day in Athens, Greece.

Cuban soldiers carry flags during a May Day rally in Havana, Cuba.

A supporter of the Russian Communist party holds a portrait of Soviet leader Joseph Stalin during a May Day rally in central Moscow, Russia.

2020 Democratic presidential candidate U.S. former Vice President Joe Biden quips that it's awkward to talk about foreign policy to reporters with an ice cream cone in his hand, at the Cone Shoppe during a two-day campaign kickoff in Monticello, Iowa.

White House adviser Kellyanne Conway speaks to reporters at the White House in Washington.

Pedestrians cross a road nest to a self-propelled howitzer during a rehearsals for the Victory Day military parade in Saint Petersburg, Russia.

Houston Rockets guard Chris Paul shoots against Golden State Warriors' Klay Thompson and Stephen Curry in game two of the second round of the 2019 NBA Playoffs. The Warriors defeated the Rockets 115-109.

A woman throws her graduation mortar board cap in the air as she poses for her photographer in front of the Lincoln Memorial in Washington.