Arctic Wonder Amazing journey to a part of the globe disappearing before our eyes. Deadly Resistance New warnings released about over-use of antibiotics. Call for Help Frantic 9-1-1 tapes in the shooting of teenager by neighborhood watch in Florida Viral Meltdown Family tries to explain naked outburst by director of documentary. Your Voice, Your Vote: Puerto Rico Primary Puerto Rico votes with 23 delegates at stake. Dangerous Twisters A powerful tornado tears through Dexter, Mich. A Soldier's Secret A portrait of Staff Sgt. Robert Bales, soldier accused of Afghan massacre. Michigan Tornadoes Caught on Tape by Survivors Rare northern twisters tear through neighborhoods just outside Detroit. Afghanistan Shooting Suspect Deployed Four Times War service, injuries and marital strife could have strained soldier. 'Pink Slime' Taste Test Cookbook author samples meat with and without ground beef filler.