Postsecondary Teacher - History Professor
A crapload of school. Most universities will require that you hold a doctoral degree, which involves fitting in about six years of school on top of your bachelor's degree, as well as completing your master's and finishing a dissertation. This is not a 75-page treatise on the deliciousness of banana cream pie. That's a dessertation. Big difference.
Sometimes a master's alone will earn you consideration at the college-level, but not usually. Plan on going the whole hog and getting yourself that doctoral degree. Besides, if you love learning as much as you should, you should welcome the opportunity to expand that brain of yours even further!