National Geographic Alien Invasion 2013 part 3

Find out in Alien Invasion as some of America's top scientific experts come together to explore the effect on mankind that contact with an advanced alien race could have. In this one-off special learn how astrophysicists, weapon designers, military strategists, biologists and anthropologists are preparing for a real alien invasion and the plan for mankind to fight back.

Can Humans Survive an Alien Invasion?