National Geographic presents two of Mother Nature?s most powerful forces in this amazing double feature release!

THE NEXT MEGA TSUNAMI Ten years after one of the most deadly tsunamis ever known, scientists are making a shocking discovery. Experts used to believe that the biggest killer waves were only generated in a handful of regions, but mounting evidence now suggests that more of the world's coasts, from the Mediterranean to Australia, could be in grave danger. Scientists are now searching for clues in the oceans, underground and back in time to uncover more evidence. But where will the next Big One strike and how destructive will it be? INSIDE THE MEGA TWISTER On May 31, 2013, National Geographic Explorer and renowned storm-chaser, Tim Samaras, sent a tweet saying Dangerous Day ahead for Oklahoma. Within 90 minutes the most extraordinary in the history of tornadoes he and his Twistex team were dead. The thunderstorm that struck El Reno, Oklahoma, on that day defined superlatives. It was the largest, one of the fastest, and - for storm chasers - the most lethal twister ever recorded on Earth. In this new film we unravel the tornado and tell its story. While it includes many first-hand accounts and harrowing videos from scientists and amateurs in pursuit of the tornado, it was also probably the best documented storm in history and these clips are part of a unique and ever-growing database, documenting every terrifying twist and turn of the storm