Across the city, protesters blocked roads, started fires at police stations and threw a Chinese flag into Victoria Harbour.
As night fell on Saturday Chinese police fired tear gas and clashed with opposition activists in Hong Kong's Kowloon district.
Police said they used tear gas to disperse the crowd after protesters lit fires outside the Tsim Sha Tsui police station
Police fired volleys of tear gas and protesters hurled bricks during clashes in a rural Hong Kong town on Saturday as several thousand activists gathered to protest an attack by a suspected triad gang at a train station last weekend.
Hong Kong’s embattled Chief Executive Carrie Lam condemned Sunday night's violent clashes.
Thousands have marched in Hong Kong to demand an independent inquiry into the police's use of excessive force and the unconditional release of those arrested.
The Sanfermines fiestas kicked off on Saturday with the much-anticipated “Chupinazo” ceremony, which sees the launching of a firework rocket to mark the start of the event.
Several hundred women dressed in bunad (Norwegian traditional clothes) took to the streets in Oslo to protest against the closure of several small birthing centres around the country.
France's "yellow vest" anti-government demonstrations recorded their lowest turnout yet on Saturday, days after a wider May Day rally was marked by violent clashes in Paris.