This thought-provoking documentary narrated by actor Martin Sheen provides a balanced look at the controversial HAARP (High-frequency Active Auroral Research Project), a high-frequency radio transmitter, or "ionospheric heater," used by the U.S. military to beam potent energy into the Earth's upper atmosphere. Whether the HAARP is advantageous or dangerous, as its fiercest critics claim, is a question that's up for debate.