But, now more than ever, troops train to go anywhere -- even inside the United States.
Just this week, Fort Bragg soldiers ran a rare training exercise in New York.
The group of soldiers flew to New York to train for a fictional scenario in which terrorists plan to strike the West Point Military Academy, the place where future Army leaders train.
Once the Fort Bragg troops landed, the commanders were briefed. They predicted what fictional enemies might do, and how they might do it.
"With the whole 9/11, anything's possible after that," said Spc. David Millburn. "That's where things are happening now. It's here on the homeland."
Within hours, soldiers set up communications and began patrolling the mountain campus.
One group of four soldiers make up what's called a fire-team. During the drill, they walked around for hours looking for anything suspicious along the perimeter.
"We're here to do a job, complete a mission, go home," said Sgt. Christian Brajas.
The paratroopers stuck to their training details for 12 straight hours. The group can be ready to go anywhere within four hours.
Most units around the country are scheduling more domestic "training ops" like this one. The soldiers at Fort Bragg have done three.