Earlier, activists had painted the names of many of the thousands of women killed each year in Mexico on the ground of the capital's iconic Zocalo plaza.
One of the largest demonstrations occurred in Chile, where thousands flooded the streets of the capital with dancing, music and angry demands for gender equality and an end to violence against women.
“They kill us, they rape us and nobody does anything,” some chanted.
National police estimated 125,000 took part in the capital and nearly 35,000 in other cities, but organizers said the crowds were far larger. Scattered clashes broke out at points when demonstrators threw rocks at police, who responded with water cannon.
Many protesters demanded that a proposed new constitution strengthen rights for women and thousands wore green scarves in a show of support for activists in neighboring Argentina, which is considering a proposal to legalize elective abortion.
Tens of thousands of women also marched through Paris, inveighing against the patriarchy.
“Enough impunity!” chanted some activists, who focused on France’s unusually high rate of women killed by their husbands. Last year, one woman was killed every two or three days by a current or former partner, and the government is increasing efforts to crack down on domestic violence.
"They should provide resources for shelters for women, victims of violence, real resources, human resources, also prevention programs for violent men,” union activist Julia Parbotin said.
Tens of thousands of women also marched in Madrid and other Spanish cities, despite concern over the spread of the new coronavirus.
A massive banner reading, “With rights, without barriers. Feminists without frontiers” in Spanish was carried at the front of the march in the capital.
Spanish health authorities did not put any restrictions on the march, but recommended that anyone with symptoms similar to those of the new coronavirus stay home. Authorities said 120,000 people participated in Madrid’s march, down from 350,000 last year.
At a school in East London, meanwhile, the duchess of Sussex, Meghan Markle, joined students in listening to speeches about women labor activists, and urged both girls and boys to respect the contributions of women every day of the year.
“For young men ... you have your mothers, sisters, girlfriends, friends in your life — protect them. Make sure they are feeling valued and safe,” she told the students.
But safety was in short supply at some events to mark the day.
The detonation of explosives triggered panic at a ceremony in Bamenda, an English-speaking town in the northwest of Cameroon. Suspicions focused on separatists who had vowed to disrupt the events. No one was killed or wounded.
Police in Bishek, the capital city of Kyrgyzstan, detained about 60 people after a group of unidentified men broke up what authorities called an unauthorized rally. About 10 women were released with charges of resisting police, the Akipress news agency reported, citing an attorney.