Mona Lisa Secrets

You'd think a girl could be left alone after 500 years, but if anything, the scrutiny of the Mona Lisa is more intense than ever. After studying the painting with 3-D laser scanners, researchers posited last week that Leonardo da Vinci's subject was pregnant, lending scientific cred to an old theory. "People have said there is an enigma to the Mona Lisa," says historian Donald Sassoon, author of Becoming Mona Lisa. "That makes it popular because people like enigmas and secret codes." True enough. Here are some puzzles scientists and writers think they've solved in just the past year.

MONA LISA SMILE A Dutch emotion- recognition program determined that her non-grin is just 83% happy. She's also 9% disgusted, 6% fearful and 2% angry.

SPEAK UP! A Japanese forensics expert claims that by analyzing her skeletal structure, he can accurately re-create her voice, which he said was low for a woman.

SMOKIN' Italian researchers say Leonardo used a blurring technique called sfumato, employing microscopic dots to create the smoky shadows near her eyes and mouth that make her stare so enigmatic.

MONA MIA A Harvard symbologist uncovered an anagram scrawled in invisible ink across the painting's face, which led to the discovery of a secret society whose sole mission was to guard the ... Wait, did we see that in a movie?