What drives some to torture and kill without remorse? Why do seemingly normal people commit acts of cruelty and violence. Researchers are exploring our inner demons, looking for ways to isolate and neutralize the source of evil in the brain. Is it really possible to change human nature?

Many religious traditions have predicted that our world will come to an apocalyptic end. Scientists agree that Earth can't last forever, but disagree on whether the universe and time itself can ever disappear. Some may hope for eternity, but the possibility of never-ending time has mind-bending implications for the present.