Here is a look at late-breaking news, upcoming events and stories that will be talked about Wednesday:
1. WHAT BOMBS IN BOSTON WERE MADE OF
The explosives builder used pressure cookers packed with metal shards, nails and ball bearings, a source tells the AP.
2. FAMILIES, FRIENDS IN MOURNING
The blasts killed an 8-year-old boy, a 29-year-old restaurant manager and a graduate student at Boston University.
3. POISON LETTER TO LAWMAKER INTERCEPTED
A letter addressed to Sen. Roger Wicker of Mississippi tests positive for ricin at a processing facility in Washington, D.C.
4. KEY COMPUTER SYSTEM CRASHES
The glitch causes American Airlines to ground all U.S. flights, leaving thousands of passengers stranded for hours.
5. REGRETS SENT AHEAD OF THATCHER'S FUNERAL
Nancy Reagan and Mikhail Gorbachev are among those who can't attend Wednesday's service for former British Prime Minister Margaret Thatcher at London's St. Paul's Cathedral.
6. ANOTHER EARTHQUAKE HITS IRAN
The second quake in less than a week renews concern about the safety of the country's nuclear reactor.
7. WHO'S GOT FIDO'S BACK
Chiropractors say they can help pets, not just people — and do it more cheaply than veterinarians.
8. VENEZUELA'S NEW LEADER CASTS BLAME
Nicolas Maduro blames the opposition and the U.S. for seven deaths and 61 injuries at a postelection protest.
9. HOW MOVIE RATINGS ARE CHANGING
The Motion Picture Association of America says it will include more prominent descriptions explaining why a movie received a particular rating — a way to better inform parents about violence in films.
10. PAT SUMMERALL DIES AT 82
The NFL player turned broadcaster spent half of his four decades calling sports while famously paired with John Madden.