The secret ghost town near New York City

Ghost towns are both eerie reminders of what once was and useful demonstrations of how the Earth moves on without us.

Filmmaker Alexander Trowbridge reflects on nature taking over after discovering Doodletown, a secret ghost town just north of New York City.

Alan Weisman, author of The World Without Us, and Cal Flyn, author of Islands of Abandonment: Life in the Post-Human Landscape, offer insights on nature's comeback after humans.