Today marks Harvey Milk Day, a celebration of the life of murdered gay rights activists.

California in 2009 acted to dedicate 22 May ‘Harvey Milk Day’, following a wave of publicity for the late activist. Hundreds around the globe have taken to social media to celebrate the day, which takes place on his birthday.

Milk was posthumously inducted into the California Hall of Fame after being portrayed by Sean Penn in the film Milk, and awarded the Presidential Medal of Freedom by Barack Obama this year.

Arnold Schwarzenegger denied a request to honour Milk’s birthday in 2008, suggesting honours were better made at the local level for the state supervisor, who was assassinated in 1978,.

Milk was the first openly gay man to be elected to public office in California, winning a post on the Board of Supervisors as a result of changes in the social makeup of San Francisco after three unsuccessful attempts to gain office.

Having finally been elected in 1977, Milk only held his position for 11 months before being assassinated by Dan White, a former colleague who had lost his position in city administration.

Milk has been described as a martyr for gay rights and a visionary. Penn received a best actor Academy Award for his portrayal of Milk.

The White House is to hold a ceremony next month to launch a stamp in honour of the assassinated politician, who became one of the first openly gay elected officials in the U.S. when he won a seat on the San Francisco Board of Supervisors in 1977.