MADRID — Thousands of people took to the streets of countries around the globe on Sunday, a day set aside by the United Nations to raise awareness of and to protest violence against women.

It was the beginning of a 16-day campaign urging individuals and organizations to fight the kind of violence that will affect more than a third of women globally during their lives, according to the United Nations.

Michelle Bachelet, the former president of Chile and the United Nations’ high commissioner for human rights, said in a video on Twitter: “I support the millions of women around the world who have dared to speak out against violence and harassment.”

Using the hashtags #MeToo, #NiUnaMenos and #NousToutes, she urged women everywhere to keep telling their stories of violence and “to demand accountability and reparation.”