From human settlers to alien visitors - when one society meets another, the results can be messy.
The Jamestown settlement may have kicked off the colonization of the New World. But, you'll hear how it also left an indelible mark on its ecosystem and the human landscape. Plus, why the Galapagos Islands haven't been the same since their most celebrated visitor set foot on their rocky shores more than a century ago.
Also: how a spider led the re-population of Krakatau after a devastating volcanic eruption... the "raining" threat of alien microbes... and one man's emergency plan for when Mars attacks.
- Charles C. Mann - author and journalist. His article "America Found and Lost" is in the May 2008 issue of National Geographic Magazine
- Travis Taylor - author of An Introduction to Planetary Defense: A Study of Modern Warfare Applied to Extra-Terrestrial Invasion
- Robert Whittaker - Professor of Biogeography at the University of Oxford
- John Rummel - Senior Scientist for Astrobiology at NASA
- Timothy Silcott - Director for Information and Development for the Charles Darwin Foundation based in Puerto Ayora, Galapagos Islands