More than 20,000 foreigners from across the globe are currently fighting in Syria and Iraq.

Many come to fight with Islamic State, the extremist group whose ranks are bolstered by men from Chechnya, North Africa, even Asia—and the women who have come to support them, whether school girls from East London or a secret bride from Melbourne, Australia. Still others fight with rebel groups and militias loyal to the Syrian government.

Here, we chronicle the global scope of their recruitment efforts via the lives and journeys of 10 men and women who traveled to the war zone. Each had his or her own reason for trading the comforts of home for a rough, austere new world. They leave behind bewildered families and communities struggling for answers.