A series of protests were held throughout the US and major international cities against President Donald Trump's often angry, populist rhetoric.
Hundreds of thousands of women's rights protestors flooded US cities on Saturday to mark President Donald Trump's first full day in office.
In the US capital, Washington, where the largest march was held, passengers on the metro bus and train network stood at 275,000 at 11 am, almost 50 percent higher than the same time for Trump's inauguration a day earlier, the Washington Metropolitan Area Transit Authority (WMATA) said.
According to Washington's deputy mayor Kevin Donahue, organisers upped their initial turnout estimate from 200,000 to half a million people faced with the flood of protesters who were continuing to pour into the capital's streets.
The US capital does not release official turnout figures, but Independence Avenue, one of the city's main arteries running along the National Mall, was so packed it was impossible to cross along 11 blocks, or around a mile (1.5 kilometres).
The crowds were such that tens of thousands were wandering on the nearby Mall itself, unable to access the main rally.
Huge sister protests were taking place in cities including Boston, New York, Denver and Chicago, where police said the event was changed from a march to a rally due to the "large crowd on hand."
The Chicago Tribune reported that 150,000 people had turned out in the city, jamming streets downtown.
By midday Saturday the protest rally had been peaceful, a sharp contrast to the day before when black-clad anti-establishment activists smashed windows, set vehicles on fire and fought with riot police who responded with stun grenades.
The protests illustrated the depth of the anger in a deeply divided country that is still recovering from the bruising 2016 campaign season.
Bonnie Norton, 35, and Jefferson Cole, 36, brought their 19-month-old daughter Maren to the march in the US capital.
"We're just disturbed by everything Trump wants to do," Norton said. Cole said he was pleased Friday's violence had not been repeated.
Thousands of women took to the streets of Sydney, London, Tokyo and other cities in Europe and Asia in "sister marches" against Trump.