El Internado is a Spanish series, which you could see a few years ago in a Antena 3(a Spanish TV channel). Seems to be a normal boarding school called "Laguna Negra", but while you are watching it you realize that strange things happen all over there. Mysteries, love, lies, conflicts, secret organizations are all over that school. A group of six students which are friends are the ones who started accidentally discovering information about things that happened in the school years ago. You then get hooked on what is going to happen next or what are they going to discover. Highly recommended series especially if you are learning Spanish.