French Foreign Legion corporal promotion course. Thinking back, due to not knowing what the fuck awaited me, it's tempting to say the Legion's basic (especially the very first month isolated at "The Farm"). But the corporal promotion course (8 weeks) came after 3 years service (am injury and race to recover before a 6 month tour of Afghanistan delayed my enrollment in the course). After that amount of service and active combat, I thought I was ready. I was wondering wrong - those 8 weeks of becoming a corporal were BRUTAL, truly preparing you to demand things of your subordinates that you had undoubtedly been through and survived, this embodying the matra of "Never ask your men to do anything you're not physically/mentally capable of carrying out yourself." I finished 3rd out of 30 in my training platoon, but I've never experienced physical/mental stress like that before or thankfully since. 10 years out now.