We got an inside look at the United States Marine Corps' intense 13-week basic training program in San Diego, California.

But last week, those same teachers and instructors returned home from their own boot camp, with sore muscles ... home to one of the United States’ Marine Corps Recruit Depots.

We got an inside look at the United States Marine Corps' intense 13-week ... 40 miles north of San Diego to Camp Pendleton, where they complete their training. Boot camp culminates with a 54 ...