Hong Kong was plunged into a fresh political crisis on Sunday night after hundreds of thousands of people took to the streets to thwart a proposed extradition law that would allow suspects to be sent to mainland China to face trial.
After seven hours of marching, organizers estimated 1,030,000 people took part, far outstripping a demonstration in 2003 when half that number hit the streets to successfully challenge government plans for tighter national security laws.
A police spokesman said police estimated 240,000 were on the march "at its peak."
Sunday's outpouring was already raising the pressure on the administration of Hong Kong Chief Executive Carrie Lam and her official backers in Beijing.
"She has to withdraw the bill and resign," veteran Democratic Party lawmaker James To told crowds gathering outside the city's parliament and government headquarters in the Admiralty business district on Sunday night.
"The whole of Hong Kong is against her."
After To spoke, thousands were still arriving, having started the march five hours earlier, filling four lanes of a major thoroughfare.
Some sat in a nearby park singing "hallelujah," but on a nearby road tensions were building after hours of peaceful protest.