Madonna has detailed how she was raped not long after she moved to New York City at the age of 19, in a revealing account of her life to date.

In an article for Harper's Bazaar magazine, the singer said she was forced on to the roof of a building at knifepoint and attacked. The first-person account, which accompanied a fashion shoot, spans Madonna's life from growing up in the US midwest and moving away from home, to her marriages and children.

"New York wasn't everything I thought it would be. It did not welcome me with open arms. The first year, I was held up at gunpoint. Raped on the roof of a building I was dragged up to with a knife in my back, and had my apartment broken into three times. I don't know why; I had nothing of value after they took my radio the first time," she wrote.

Madonna says her breath was taken away by the size and scale of the city, and she was "scared shitless and freaked out by the smell of piss and vomit everywhere".

"Trying to be a professional dancer, paying my rent by posing nude for art classes, staring at people staring at me naked. Daring them to think of me as anything but a form they were trying to capture with their pencils and charcoal. I was defiant. Hell-bent on surviving. On making it. But it was hard and it was lonely, and I had to dare myself every day to keep going," she said.

The move to England, following her marriage to the film director Guy Ritchie, "wasn't easy for me".

"Just because we speak the same language doesn't mean we speak the same language. I didn't understand that there was still a class system. I didn't understand pub culture. I didn't understand that being openly ambitious was frowned upon. Once again I felt alone. But I stuck it out and I found my way, and I grew to love English wit, Georgian architecture, sticky toffee pudding, and the English countryside. There is nothing more beautiful than the English countryside."

Madonna described the decision to adopt her son David from Malawi as "another daring chapter" in her life and one which threw her back into "another shit storm".

"I was accused of kidnapping, child trafficking, using my celebrity muscle to jump ahead in the line, bribing government officials, witchcraft, you name it," she wrote. "This was an eye-opening experience. A real low point in my life. I could get my head around people giving me a hard time for simulating masturbation onstage or publishing my Sex book, even kissing Britney Spears at an awards show, but trying to save a child's life was not something I thought I would be punished for. Friends tried to cheer me up by telling me to think of it all as labour pains that we all have to go through when we give birth. This was vaguely comforting. In any case, I got through it. I survived."

When she adopted her second child, Mercy James, the singer said she put her "armour on".

"I tried to be more prepared. I braced myself. This time I was accused by a female Malawian judge that because I was divorced, I was an unfit mother. I fought the supreme court and I won. It took almost another year and many lawyers. I still got the shit kicked out of me, but it didn't hurt as much. And looking back, I do not regret one moment of the fight."