Citizens' Military Training Camp
Citizens' Military Training Camps (CMTC) were United States government authorized military training programs held annually each summer during the years 1921 to 1940. CMTC camps differed from National Guard and Organized Reserve training in that the program allowed young male citizens age 17-24 to obtain basic military training without incurring an obligation to be called up for active duty.
Source: Wikipedia — Citizens' Military Training Camp (CC BY-SA 4.0)