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.

The war on extremism continues across the globe -- from Iraq to Colombia to Afghanistan.

As the battle of Mosul nears an end, fighting extremism in Trinidad and Tobago begins.

As U.S. forces battle violent extremism around the globe, no setting has been more vexing over the last decade and a half than Afghanistan. Now Marines have returned to the country to advise and assist the Afghan army, which has been struggling badly in fighting with the Taliban. As the Marines work to better the fortunes of their allies, an officer burns the midnight oil to watch on Skype as his son is born back home.

In Afghanistan, U.S. Marines continue to work to overcome challenges while advising and assisting the Afghan National Army. Meanwhile, the Pentagon keeps focus on extremist threats around the globe. Military leaders discuss the growing concerns in Africa, deploying special operations forces uniquely equipped to handle threats there. And in Panama, a U.S. special agent joins local security forces tracking migrants for terrorist threats.