This university lecturer who became mayor of Tehran and then president of Iran is now America's nemesis. Today Ahmadinejad is controversial, defiant and feared. But he first shocked the world when he called the holocaust a myth.

Christiane Amanpour follows the New York Philharmonic to Pyongyang, capital of the Democratic People's Republic of Korea (North Korea). An unprecedented view of a country that is as secretive as it is isolated.

Today, nearly 50 million Americans, have no health insurance. Once the envy of the world, our health care system stands at a crossroads. This program takes a closer look at the problem and how the next election might shape a solution.

The government is spending your tax dollars to save the environment - even as it enacts policies that endanger it. Miles O'Brien explores how Washington is spending your money in ways that may block the path to a safer environment.

There are perhaps no greater heroes than the firefighters of 9/11. Larry King had the privilege of visiting a fire station on the front line of that terrible attack. These are the heroes of Firehouse 54-4.

Doctor, divorcee... prostitute, prisoner. Meet the women who risk their lives to tell you the reality of terror and hope in Iraq today. A CNN Special Investigations Unit presentation.

A two-part documentary that examines our changing planet. This global investigation looks at four key issues: climate change, vanishing habitats, disappearing species and human population growth. (Part 1 of 2)

A two-part documentary that examines our changing planet. This global investigation looks at four key issues: climate change, vanishing habitats, disappearing species and human population growth. (Part 2 of 2)

This CNN Special Investigations Unit program takes a look at how thieves exploit stolen identities to bilk banks and cheat credit card companies. Tune in to learn more about the blueprint of modern-day bank robberies.

This fascinating documentary, narrated by Liam Neeson, examines how a small group of followers survived persecution and internal divisions to grow into one of the world's most widespread religions.