Several hundred protesters gathered in Brasilia to demand the impeachment of President Dilma Rousseff after they completed a 1,000-kilometer (650-mile) march on the capital.
Polls opened in Ireland for a historic referendum on allowing same-sex marriage that is backed by all the main political parties but opposed by the Catholic Church.
Prince announced a peace concert in Baltimore on Mother's Day after the death in police custody of an African American man sparked sometimes violent protests.
Baltimore lifted a curfew that was imposed across the US East Coast city following widespread riots, as thousands of National Guard troops began to pull out.
Several hundred people protested in New York demanding police reform and justice for the African-American man who died from injuries sustained in custody in Baltimore.
Bare-chested Femen activists making Nazi salutes disrupted a speech by France's far-right leader Marine Le Pen at her National Front party's traditional May 1 rally in Paris.
Hundreds of thousands of Brazilians took to the streets, venting anger over government corruption and economic drift a month after larger protests gathered.
Thousands of Hungarians took to the streets in separate national day demonstrations to both protest against, and voice support for, Prime Minister Viktor Orban.
Seven months under the wrong kind of spotlight is taking its toll on Ferguson as it tries to move past the dark shadow cast by the police killing of unarmed black teenager.
Tens of thousands of people marched in central Moscow to honour the memory of opposition leader Boris Nemtsov, who was gunned down near the Kremlin in the highest-profile assassination of Vladimir Putin's rule.
The United States and Latin American nations voiced concerns Friday over political tensions in Venezuela after the socialist government arrested the opposition mayor of Caracas in an alleged coup plot.