Italian women are holding nationwide protests against embattled Prime Minister Silvio Berlusconi.
The demonstrations in dozens of cities were due to be attended by high-profile personalities, including opposition politician Rosy Bindi.
Organisers say Mr Berlusconi has damaged the standing of women with his recent sex scandals.
He has denied any wrongdoing, saying the current investigations against him are politically motivated.
This week he said a request by prosecutors in Milan to have him put on trial immediately for allegedly paying for sex with an underage girl is "disgusting", saying the prosecutors' case was a "pretext" to oust him.
He denies paying for sex with Karima El Mahroug - a Moroccan nightclub dancer also known as Ruby - when she was 17, and abusing his power to get her released by police after she was detained in another case.
A magistrate will now decide if there is enough evidence to proceed to trial.
If convicted, Mr Berlusconi could face up to 15 years in prison.
Although frequenting prostitutes is not a crime in Italy, having sex with one under the age of 18 is an offence that carries a prison sentence.Debasing women?
The day of protest has a title - Se non ora, quando? (If not now, when?) - designed to express the frustration of those Italian women who are asking what it will take for Silvio Berlusconi to resign, says the BBC's Duncan Kennedy in Rome.
They say his scandals have profoundly weakened women's standing in Italy by depicting them as objects.
Thousands of protesters marched through more than 60 towns and cities nationwide, including Naples, Palermo, Bari, Trieste and Venice.
Rome's Piazza del popolo - or people's square - was crammed with tens of thousands of women and some men in an act of solidarity.
Protests have also been held internationally, with one protest in Tokyo and more planned in other European countries as well as the US.
Led by leading female figures in society, they carried banners calling for Berlusconi to resign and chanted slogans such as: "Italy is not a brothel".
"We are asking all women to defend the value of our dignity, and we are asking men, if not now, when?" organisers said on the protest website.
Marching through Naples, the mayor of the southern Italian city, Rosa Russo Iervolino, said: "The importance of this rally is in the common participation of men and women, young and old, intellectuals and workers."
Despite all the recent negative publicity, Mr Berlusconi's opinion poll ratings are still at around 35%.
The billionaire prime minister also retains the support of his ruling coalition allies the Northern League, who do not want to see him quit, adds our correspondent.
But there are millions of other Italians, both male and female, who believe the media mogul's personal life has debased women, making Italy a laughing stock, and that he should now stand aside.
The prosecutors have submitted two sets of documents detailing the evidence against the prime minister.
They allegedly include proof that payments were made by his aides to a "significant number" of young women, including Miss Mahroug.
Last month, Italy's Constitutional Court amended a law granting members of the government temporary immunity from prosecution. The court decided that individual judges should be allowed to decide whether ministers should be tried while in office.