The 11th annual Denim Day was observed Wednesday in Los Angeles with thousands of people wearing blue jeans as part of a campaign to raise awareness and educate the public about rape and sexual assault.

Peace over Violence, a non-profit social service group in Los Angeles, started Denim Day in 1999 when an Italian court overturned a rape conviction partially because the victim was wearing tight jeans -- something the justices reasoned the suspect couldn't have removed without the victim's help.

A presentation by Patti Giggans, executive director of Peace Over Violence, and actress Calista Flockhart, the group's spokeswoman, is expected later at the Los Angeles City Council meeting on the issue of sexual violence and violence prevention.

Flockhart will also visit a downtown Los Angeles high school to talk to students and present statistics on sexual violence, with rallies being organized at other schools in recognition of the day.

In West Hollywood, city employees were wearing denim and gathered outside City Hall Wednesday morning for an annual Denim Day employee photograph, according to organizers.

The Los Angeles-based designer jeans maker 7 For All Mankind announced it would donate 10 percent of its denim sales Wednesday to Peace Over Violence, which provides counseling to sexual assault victims and prevention services.