The White House issued a terror alert this weekend, asking Americans traveling to Europe to be vigilant, especially at popular tourist spots and on public transportation. The alert comes after a critical mass of evidence emerged over the last few months pointing to terrorist plans targeting European countries. We have the details and the latest from Scott Shane, National Security Reporter for the New York Times.

Researchers at Northeastern University have found that in cities like Chicago, Milwaukee, Cleveland and Syracuse, New York, black students go to almost entirely black schools, and white students go to schools that are almost entirely white. Researchers also found that, while Latino segregation is highest in Los Angeles, four New England cities also have high levels of Latino student segregation. One of the researchers came to the conclusion that this fall students returned to schools that are largely separate and unequal. We speak with study co-author Delores Acevedo-Garcia, associate director of the Institute on Urban Health Research at Northeastern University.

Rahm Emanuel's tenure as White House chief of staff may be doing more harm than good for his bid to become Chicago's next mayor. Emanuel is on the campaign trail today, kicking off what he's calling a "Tell It Like It Is" listening tour of the city. Some of his opponents have leapt at the chance to criticize Emanuel for policies the Obama administration has backed, and have labeled him a carpetbagger. Ray Long covers politics for the Chicago Tribune and gives us his take on Emanuel's fledgling candidacy.

From 1946-1948, the U.S. government deliberately and secretly infected hundreds of Guatemalans with syphilis and gonorrhea as part of a public health study on sexually transmitted diseases. Most of those infected were treated, but at least one died. They were prisoners, soldiers and mental patients who likely had no idea what was happening to them. Virtually no one else would know what happened to them either if it weren't for Wellesley professor Susan Reverby, who stumbled across evidence of the study while researching the now infamous syphilis study conducted in Tuskegee, Alabama.

A new exhibit at the Smithsonian American Art Museum explores the connections between Norman Rockwell's iconic images of American life and American fillmmakers. The exhibit features Rockwell paintings from the collections of directors Steven Spielberg and George Lucas. The BBC's Jane O'Brien reports on the influence Rockwell had on two of the world's best known filmmakers.

• Ashley MacIsaac, "Sleepy Maggie"
• Nathan Milstein, "Bach: Sonatas and Partitas for Solo Violin"
• Dean & Britta, "Herringbone Tweed"
• Ahmad Jamal, "Patterns"
• Kar Kar Madison, "Boubacar Traore"
• Christian McBride, "Theme for Kareem"
• Detroit Symphony Orchestra, playing John Williams' “The Horn Concerto V. Nocturne: The Crimson Day Withdraws”
• John Williams, “Toy Planes, Home and Hearth (Chopin Mazurka Opus 17 No. 4)”