Chief video correspondent Graham Flanagan got an inside look at what it's like on the first day for new freshmen, known as knobs, at the Citadel in Charleston, South Carolina.
The US Army trains soldiers for jungle warfare at the 25th Infantry Division's Lightning Academy on the island of Oahu in Hawaii.
Airman 1st Class Devyn, a US Air Force DAGRE team member, walks us through every piece of equipment he would carry with him on a mission as an air commando.