NOVA

How did investigators transform the chaos of the Boston Marathon Bombing into a coherent trail of clues, pointing to the accused killers?

On May 20th 2013, a ferocious F5 tornado over a mile wide tore through Moore, Oklahoma, inflicting 24 deaths and obliterating entire neighborhoods. It was the third time an exceptionally violent tornado had struck the city in 14 years. Yet predicting when and where these killer storms will hit still poses a huge challenge.

From PBS - NOVA returns to Ground Zero to witness the completion of One World Trade Center.

From PBS - One year after Hurricane Sandy's deadly strike, NOVA investigates the critical question raised by this historic storm: What can we do to prepare ourselves for the next Sandy?

From PBS and NOVA: Cold Case JFK. For decades, the assassination of John F. Kennedy has fueled dark rumors of conspiracies and mishandled evidence. Now, fifty years later, NOVA asks: Could modern investigators do better?

Between the blue sky above and the infinite blackness beyond lies a frontier that scientists have only just begun to investigate. In "At the Edge of Space," NOVA takes viewers on a spectacular exploration of the Earth-space boundary that's home to some of nature's most puzzling and alluring phenomena: the shimmering aurora, streaking meteors, and fleeting flashes that shoot upwards from thunderclouds, known as sprites.

The asteroid that exploded over Siberia--injuring more than 1,000 and damaging buildings in six cities--was a shocking reminder that Earth is a target in a cosmic shooting range. From the width of a football field to the size of a small city, these space rocks have the potential to be killers. In a collision with Earth, they could set off deadly blast waves, raging fires and colossal tidal waves.