Countdown to Impact Format:DVD To pay tribute to his

To pay tribute to his great grandfather

a filmmaker

A strained relationship between him and his sister leads Ian to discover there are complicated circumstances behind the life he didn't realize he was living

the house fights back and a real-life tragedy strikes nearby

a grown-up Henry Mills leaves home in search of his own destiny

Countdown to Impact Format:DVD To pay tribute to hisFor the first time in the history of space exploration, scientists spotted and tracked an asteroid on a collision course with Earth. About the size of a truck, the asteroid slammed into the Nubian Desert in Sudan, in nearly the exact spot and only a few seconds from the time scientists had predicted. Now, together with NASA scientists, National Geographic joins researchers as they examine the remnants of the asteroid to unlock the clues to help us