The secret behind the buildings bomb resistance can be found inside.

UNESCO: Culture

But the truth is, no one knows the secret behind this ancient mystery.

BBC: Laos�� strange plain of jars

Mr. JOHN WALKE (Natural Resources Defense Council): The dirty little secret behind the Bush administration's air pollution agenda is to stretch out the time for power plants to clean up over the next two decades and to call that progress while eliminating clean air protections that would require them to clean up today.

NPR: EPA Proposal Eases Rules on Pollution Controls