Reality television is a genre of television programming that documents ostensibly unscripted real-life situations, and often features an otherwise unknown cast. It differs from documentary television in that the focus tends to be on drama and personal conflict, rather than simply educating viewers. Reality TV programs also often bring participants into situations and environments that they would otherwise never be a part of. The genre has various standard tropes, including "confessionals" used by cast members to express their thoughts, which often double as the shows' narration. In competition-based reality shows, a notable subset, there are other common elements such as one participant being eliminated per episode, a panel of judges, and the concept of immunity from elimination.The genre may have begun in earnest in 1991 with the Dutch series Nummer 28, which was the first show to bring together strangers and record their interactions. It then exploded as a phenomenon in the late 1990s and early 2000s with the global success of the series Survivor, Idols and Big Brother. These shows and a number of others (usually also competition-based) became global franchises, spawning local versions in dozens of countries. Reality television as a whole has become a fixture of television programming. In the United States, various channels have retooled themselves to focus on reality programs, most famously MTV, which began in 1981 as a music video pioneer, before switching to a nearly all-reality format in the early 2000s.