
What if an extra-terrestrial force attacked Earth? What might that look like and how will the people of Earth respond? Consulting a cast of world-renowned scientists, survival experts and defense experts, National Geographic explores this frightening scenario. Experts reveal what could motivate alien invaders to attack Earth, and speculate on how the attack might play out, the strategy alien invaders might use, and the most effective ways for humans to respond.
Narrator (voice)

Self - SETI Institute

Self - U.K. Ministry of Defense

Self - Director of Defense Studies, West Point
Self - Theoretical Physicist (archive footage)

Self - USAF Air Command and Staff College
Self - Physicist & Author
Self - Co-Author, Alien Invasion: How to Defend Earth
Self - Author, Contact with Alien Civilizations
Self
Self - Author, Live Free or Die
Self - Author: Adventures Among Ants
Self - Washington State University
Self - Author, Emergency

Self - onPoint Tactical
Self - Gunnery Sergeant, USMC
Self - High Altitude Research Corp.
Survivor
Laboratory Scientist

Survivor
Scientist

Survivor
News Correspondent

Survivor
Resistance Leader
Survival Expert

Resistance Fighter

Survivor
Survivor
Astronomer

Survivor

Resistance Fighter
Agent Patterson
Survivor

Human Resistance Leader