"This is still a very young industry, with a lot of claims out there that are sometimes difficult to believe," said al Darzins, a group manager at the lab's National Bioenergy Center.

And it's widely thought that the devastation caused at the World Trade Center and Pentagon couldn't have taken place without al-Zawahiri's influence.

Alcoa Inc. has a 6-foot-tall robot spokesperson, Al, who hosted a recent Robot Block Party at the Carnegie Science Center.