By Nate Lippens
Special to MSN Music

Madonna is one of the biggest pop stars of all time. Her malleable persona has kept her at the top of the charts and in the public eye for nearly a quarter of a century.  By blurring distinctions between her music, her videos and her sexuality, she has redefined pop stardom. Here's a look back at some of the key moments that catapulted Madonna to icon status.

"Borderline"
After a string of club and dance hits, the single "Borderline" became Madonna's first Top 10 hit in March 1984. The catchy song introduced the flamboyant performer to the public and began a remarkable string of 17 consecutive Top 10 hits.

"Like a Virgin"
At the first MTV Video Music Awards, Madonna writhed on top of a cake, wearing a bustier, gown, lacy stockings and "Boy Toy" belt, in a choreographed combination of wedding and bachelor party. Her highly sexualized performance of the controversial and popular song rocketed her to instant stardom.

"Material Girl"
The video, with its "Diamonds Are a Girl's Best Friend" homage, portrayed Madonna as a gleefully gold-digging blonde. Some felt it typified the greed of the '80s whereas others saw it as a tongue-in-cheek send-up. The international press would later apply the song's title to the icon.

"Desperately Seeking Susan"
This 1985 box-office hit directed by Susan Seidelman launched Madonna's film career with a role that drew heavily from her own persona and look. Thousands of teenage girls adopted her trademark appearance from the film: lace tops, skirts coupled with capri pants, fishnet stockings, jewelry bearing the Christian cross, and bleached hair with dark roots.

"Papa Don't Preach"
"Papa Don't Preach" became her fourth No. 1 hit in the United States. The song and video showed an unmarried pregnant narrator choosing to keep her baby. The song sparked controversy among conservatives and liberals, who saw it as irresponsible considering her teenage fan base.

"Like a Prayer"
Condemned by the Vatican, the video for "Like a Prayer" caused an uproar. Featuring stigmata, burning crosses, and a black man portraying Jesus, the video was Madonna's most provocative statement to date. It depicts a black man who comes to the aid of a white woman being murdered by white men. The man is  falsely arrested for the crime, and. Madonna, who witnessed the crime, fights for his release.

Blonde Ambition Tour
From April to August 1990, Madonna toured Japan, North America and Europe on her Blonde Ambition World Tour. The highly theatrical show featured religious and sexual themes and symbolism. It also drew controversy for a performance of "Like a Virgin," during which she simulated masturbation. The tour was hugely popular, and its production values and narrative threads changed the look and approach for many such extravaganzas.

"Truth or Dare"
Spun off the Blonde Ambition Tour, this documentary (also known as "In Bed With Madonna" outside North America) was received positive reviews and strong box-office earnings during spring 1991. It ventured behind the scenes of her tour and included scenes with her gay male dancers and her personal life.

"Justify My Love"
The music video for "Justify My Love," directed by Jean-Baptiste Mondino, showed Madonna in suggestive scenes of S & M, bondage, same-sex kissing and brief nudity. It was deemed too sexually explicit for MTV and was subsequently banned from the network. Warner Bros. Records released the video as a video single, and it became the highest-selling video single of all time.

"Sex"
Later that year, Madonna released "Sex," a soft-core erotic book featuring photographs of herself with models, and other celebrities, including Isabella Rossellini, Vanilla Ice and Naomi Campbell . It received scathing reviews and inflamed intense controversy yet sold well and opened up a discussion about pornography and art that seems comparatively tame today.

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