Wednesday, April 20, 9-11 pm ET
Find out what is causing the invasion of alien species of plants and animals, and what can be done to stop the rising tide.

Alien species of plants and animals have invaded every continent. They have enormous powers;
they spread disease; they devour our buildings. Some are destroying the very land under our feet. Think of them as the first wave of an assault that could drive the greatest mass extinction since the end of the dinosaurs.