New York, Los Angeles, and Washington, D.C. have stepped up police presence on transit, at tourist attractions, and near hotels.
If there's an uplifting lesson from Boston, it may be the many people who will overcome the trauma of tragedy.
Race officials are reviewing security precautions with local police after the attacks in Boston Monday.
Modern-day militia activists have attempted to hold rallies on this holiday in recent years.
Maps of where blasts occurred, the race course, the streets in question.
Scores are rising as teachers track data and look for patterns to improve classroom learning.
Inside the Hermit Kingdom.
An intriguing theory about the geography of the "middle ground" on guns.
"From day one we were getting a lot of phone calls from nervous patients."
It's not the spread-out icons of Phoenix and Las Vegas, but rather pockets of the South Atlantic, Texas and the Pacific Northwest.
Also, politicians in Racine ban weapons (except for their own) and New York battles a slimy lake menace.
Three programs to watch as federal budget negotiations kick off.
A country known for its stiff upper lip lets loose with tears and champagne.
For the destructive raid on Zucotti Park.
The mayor on why his city is now a magnet for traditional businesses and startups alike.
African Americans waited an average of 23 minutes to vote in the 2012 election, compared to 12 minutes for whites.
Climate change is forcing a showdown between vineyards and sensitive habitats.