Osama Bin Laden Dead: U.S. Remembers 9/11

Tornado Twists Through Okla.

Twister ripped apart homes from Newcastle to Moore, a path of 12 miles.

Tornado Chasers Catch Outbreak on Tape

ABC News' Ginger Zee chases tornadoes during a large breakout of storms.

Aimee Copeland Gets Bionic Hands

Touch Bionics donated prosthetics to Georgia woman, 25, who lost her hands to flesh-eating bacteria.

Cops Kill Hofstra Student in Home Invasion Standoff

A police officer made a split-second decision when a man held Andrea Rebello hostage.

$590 Million Powerball Ticket Sold in Florida

The search is on for the lucky person who purchased the winning ticket.

Wait Begins for Owner of Winning Powerball Ticket

One ticket worth a half-billion dollars was purchased in small Florida town of Zephyrhills.

May 1999: Historic Okla. Tornado

EF-5 tornado killed 42 people in the Oklahoma City area.

Tornado Rips Through Moore, Okla.

The National Weather Service says tornado had wind speeds up to 200 mph.

Rhode Island Student Disappears on Drive Home

Matthew Royer, 21, never arrived at his Pennsylvania home after leaving the University of Rhode Island.

Aimee Copeland's Comeback After Flesh-Eating Bacteria

Woman who lost her limbs talks about her positive outlook on life.

Assessing the Injured from the Oklahoma Tornado

Hospital worker Brook Cayot discusses treating victims of the Oklahoma tornado.

Monster Twisters Caught on Tape

At least four tornadoes touch down in Kansas; heavy rain and winds on its way.

Tornadoes Rip Through Homes in Oklahoma

Powerful tornadoes swept across the Midwest leaving a path of destruction and debris.

Jodi Arias Judge Denies Attorneys' Request to Withdraw

Kirk Nurmi asked for a mistrial in the death penalty phase citing prosecutorial misconduct.