An unprecedented look deep inside the war against violent extremism.
As the war on extremism continues globally, the battle for western Mosul begins in Iraq.
As the battle of Mosul nears an end, fighting extremism in Trinidad and Tobago begins.
In Afghanistan, the Marines work with local fighters as they battle the Taliban.
The United States continues its global war against extremism in Afghanistan, Africa and Panama.
U.S. Marines prepare to return home from Afghanistan, but they are still surrounded by reminders of the dangers haunting the country.