There are some things you can count on in life: The sun will rise and set, the seasons will change, and pretty much every time you turn on cable television you're likely to find an episode of "Law & Order." The show is so ubiquitous and so long running it has even been used to chart the cultural and technological history of the United States. In 2012, artist Jeff Thompson received a commission for a project he called "Computers on Law & Order," where he took screenshots of all the computers that appeared onscreen in the show's 20-year history. He concluded that "Law & Order" was "an even more interesting cultural artifact" than he expected [source: Rhizome]. In spite of its enduring presence, however, "Law & Order" is not the longest-running TV show of all time.
If you take the number of seasons (or the length of time a show has aired) as your benchmark, NBC's "Meet the Press" is the winner, with 66 seasons and 67 years on air [source: Today].
But in order to determine which is the longest-running show, you'll also need to consider how you want to define the term "TV show." If you include all television programming in your definition, then "Meet the Press" is still the standout. However, if you're more interested in determining the longest-running show for a particular genre, then "Guiding Light" — a daytime soap that aired between 1952 and 2009 — is the longest-running dramatic series of all time [source: Carter]. Meanwhile, "Hockey Night in Canada," the Canadian Broadcasting Corporation's weekly National Hockey League broadcast, also began airing in 1952 and continues to the present day, making it the longest-running sportscast.
No matter which metrics and definitions you decide to use, television's longest-running shows are fascinating windows into all kinds of history. From "The Simpsons" to "Hollywood Squares," explore lots more longest-running television links in the next section.