Narrator: This Marine Corps recruit isn't actually injured ... Narrator: It's part of their final test at boot camp, known as the Crucible, a 54-hour event that all recruits must complete.

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

Brooklier, 29, enlisted in the Marine Corps in January ... Toward the end of boot camp, Brooklier finally got to do the Crucible. And it was indeed challenging, both physically and mentally ...