National Geographic: Inside the Mega Twister (2015) is a Documentary film that follows the tornado that struck El Reno, Oklahoma, on May 31, 2013, defined superlatives. It was the largest twister ever recorded on Earth. National Geographic: Inside the Mega Twister is not currently listed with streaming providers in your selected region, but availability can change over time. It has a user rating of 6.0 out of 10 from 1 votes. Fans of documentary movies may also want to explore similar titles below.