In her prime, Elizabeth Taylor wasn't just considered the most stunning starlet in Hollywood, but the most beautiful woman in the world.
But what was it about her beauty, exactly, that made it so special?
Of course, she had those unforgettable violet eyes and cascading mane of dark hair. But scientists say research has helped shed even more light on what made Taylor's beauty so rare.
"I think she's one of these lavish beauties," said Nancy Etcoff, a Harvard psychologist and author of "Survival of the Prettiest: The Science of Beauty. "I think Richard Burton called her a 'miracle of construction.'"
Taylor's 'Hyper-Femininity' Contributed to Beauty, Scientist Says
The violet eyes, Taylor's white skin and raven hair may be captivating on their own, but Etcoff said that it was the combination of them that likely boosted her allure.
"A higher contrast tends to make the face look more feminine," she said.
In studies conducted by Richard Russell, a psychology professor at Gettysburg College, she said, participants found faces with greater contrast between features (like eyes and lips) and skin to be more feminine than faces with less contrast.
Taylor's signature bold lip color and dark, made-up eyes further contributed to the effect, she said.
"She also had a feature that most people wouldn't think of as contributing to attractiveness, but really does, which is a small, gracile jaw," she said. "Which means a jaw that is kind of small and very hyper-feminine."
In puberty, men's faces develop brow ridges and square jaws, but women's features remain less pronounced in those areas, she said.
"If we think that one sign of beauty, and there are many others, is hyperfemininity, then she has that exaggerated lower face with large lips and a small jaw," Etcoff said. "That's one aspect of beauty that's very noticeable in her face."
Taylor's Hour-Glass Figure Was Exaggerated
Taylor's face isn't the only attribute that science has found to be attractive.
"She combines that beautiful face with a very beautiful body, which is beautiful in a particular way," said Etcoff. "She's almost what we would call a super-normal stimulus, which means that her hourglass figure is exaggerated."
Taylor's two-time husband Richard Burton may have called the actress's breasts "apocalyptic" and able to "topple empires," she said, but they were paired with a tiny, little waist.
Science has shown that the the ideal waist-to-hip ratio is 0.7, she said, but Taylor's hourglass figure supposedly boasted a 0.6 ratio.
"You think of her as voluptuous, but that combined with a tiny waist made her exaggeratedly feminine and attractive," she said.
Stephen Link, a psychologist at the University of California San Diego, said his research has shown that there are even more mathematical ratios underlying Taylor's lauded looks.
In 2009, he and two colleagues, Pamela Pallett, now with Dartmouth College, and Kang Lee of the University of Toronto, tried to uncover the facial proportions in people considered to be most attractive.
"Your ideal feminine face is something that's been talked about for so long -- 'the face that launched a thousand ships,'" he said. "When you hear that, you conjure up a face, I wanted to measure what it was about that face that made it ideal."
They asked about 160 students to look at hundreds of faces with different proportions and discovered their "golden ratios": When the vertical distance between a woman's eyes and mouth was about 36 percent of the face's length, and when the horizontal distance between the eyes was about 46 percent of the face's width, the face was judged to be more attractive.
Link said Taylor was a perfect example.
"She was right there with the proportions of the beautiful face," he said. "Elizabeth Taylor was a great beauty and she has those proportions that are those of the ideal."
Of course, non-scientists are quick to point out that beauty is still in the eye of the beholder -- and the social context that shapes what they see.
Lois Banner, professor of history and gender studies at the University of Southern California and author of "American Beauty," said that while Taylor's natural looks certainly contributed to her fame, her image was also bolstered by smart publicity, heavy studio support and her many love affairs.
"Beauty is a quality, in someone of that great public stature, beauty is something that operates on all kinds of levels. It's not just the initial meeting the cultural expectations and standards for beauty," she said.
Historian: Taylor Related to the Beauty Standards of Her Time
Taylor was tapped to be a star early in her career, Banner said, during a time when there were fewer Hollywood stars. That meant more pages in fan magazines, more glamorous roles sent her way and more attention lavished on her by studios and admirers.
Her many lovers also helped create an image of the highly sought-after siren.
"[The public] always likes to see stars marrying exotic men they never dreamed they could marry," she said. "On one hand she lived an ordinary life, on the other hand she lived an extraordinary life. So there were a lot of fantasy worlds that she was actualizing."
Even Taylor's many personal battles, with drugs and alcohol, helped lift her profile by keeping her in the public eye, she said.
"She was a struggling star, and the public loves a struggling star," she said.
But the 1950s was a "particular time" in the history of beauty, Banner said, and though Taylor related to the standards of her era, it's difficult to say how she would be perceived if her career peaked now.
"We have different standards of beauty today. We see a lot of things as beautiful today they didn't see then," she said. "That doesn't mean Elizabeth Taylor wouldn't be considered beautiful today, but I doubt it would reach the extent that it did then."